pith. sign in

arxiv: 2606.19021 · v1 · pith:QXROBGATnew · submitted 2026-06-17 · 💻 cs.CE

On a variational model for phase transformation in SiO2 glass

Pith reviewed 2026-06-26 19:01 UTC · model grok-4.3

classification 💻 cs.CE
keywords SiO2 glassphase transformationvariational modelcompactionelastic modulivolume fractionshydrostatic pressure
0
0 comments X

The pith

A variational model treats SiO2 glass compaction under pressure as a binary phase transformation of volume fractions.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper develops a variational framework for the evolution of SiO2 glass under hydrostatic pressure by modeling the process as a binary phase transformation. It draws on an existing multi-phase transformation model for inelastic materials but assumes isothermal conditions and tracks only the macroscopic volume fractions of the two phases. Microstructures such as shear bands are not resolved. Numerical examples demonstrate that the model reproduces the sigmoidal stress response and the linked changes in elastic moduli and volume that are seen in experiments.

Core claim

The central claim is that the compaction of SiO2 glass can be captured by a variational model of binary phase transformation in which two volume fractions coexist, producing the observed reduction in elastic moduli and the complex inelastic response under pressure, with the resulting predictions matching experimental data closely.

What carries the argument

Variational framework for multi-phase transformations in inelastic materials, restricted here to a binary phase transformation that resolves only volume fractions.

If this is right

  • The model directly relates measured drops in elastic moduli to the volume fraction change during compaction.
  • Numerical simulations illustrate how pressure drives the coexistence of the two phases and the resulting inelastic behavior.
  • The framework reproduces experimental stress-strain responses without needing explicit microstructure geometry.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same binary-volume-fraction approach might be tested on other glasses that exhibit similar sigmoidal compaction curves.
  • Adding a sub-model for microstructure evolution could later link local patterns such as disclinations to the macroscopic moduli changes.
  • Relaxing the isothermal assumption would allow exploration of temperature-dependent shifts in the transformation pressure.

Load-bearing premise

The typical sigmoidal stress response is interpreted as the signature of a binary phase transformation occurring under isothermal conditions, with only volume fractions resolved.

What would settle it

New hydrostatic compression experiments that measure elastic moduli and volume change versus pressure and yield curves that deviate systematically from the model's predictions.

Figures

Figures reproduced from arXiv: 2606.19021 by Klaus Hackl, Sarah Dinkelacker-Steinhoff.

Figure 1
Figure 1. Figure 1: Sigmoidal behavior of pressure a function of the compression ratio. The data [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Bulk modulus K against volumetric strain [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Visualisation of potentials as function of volumetric strain [PITH_FULL_IMAGE:figures/full_fig_p008_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Development of separated energy potentials [PITH_FULL_IMAGE:figures/full_fig_p011_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Isothermal material point analysis. From (a) to (d), volume fraction as [PITH_FULL_IMAGE:figures/full_fig_p012_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Bulk modulus K as function of effective transformation strain [PITH_FULL_IMAGE:figures/full_fig_p013_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Illustration of the two-dimensional geometry on the x - y plane on the left side [PITH_FULL_IMAGE:figures/full_fig_p014_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Representation of spreading bulb at two time steps n = [665, 1000]. [PITH_FULL_IMAGE:figures/full_fig_p015_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Equivalent von Mises stress against hydrostatic pressure P. [PITH_FULL_IMAGE:figures/full_fig_p016_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Progression of the model at one Gaussian point. Data are taken from the 2d [PITH_FULL_IMAGE:figures/full_fig_p017_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: Geometric setting for the uniaxial compression and the coupled shear - [PITH_FULL_IMAGE:figures/full_fig_p018_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: Contour plot of phase transformation during uniaxial compression at five [PITH_FULL_IMAGE:figures/full_fig_p019_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: Time evolution over position x at y = h/2 for the rectangular plate during an [PITH_FULL_IMAGE:figures/full_fig_p020_13.png] view at source ↗
Figure 14
Figure 14. Figure 14: Behavior of a single Gaussian point during compression. Comparison of two [PITH_FULL_IMAGE:figures/full_fig_p021_14.png] view at source ↗
Figure 15
Figure 15. Figure 15: Illustration of boundary conditions and displacements during a coupled shear [PITH_FULL_IMAGE:figures/full_fig_p022_15.png] view at source ↗
Figure 16
Figure 16. Figure 16: Contour plots of a coupled shear-compression test at time step number n = [PITH_FULL_IMAGE:figures/full_fig_p022_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: From (a) to (c), time development of average element data with range of [PITH_FULL_IMAGE:figures/full_fig_p024_17.png] view at source ↗
Figure 18
Figure 18. Figure 18: Geometric illustration of the two-dimensional square plate with a circular [PITH_FULL_IMAGE:figures/full_fig_p025_18.png] view at source ↗
Figure 19
Figure 19. Figure 19: Contour plot of bulk modulus K and deviatoric stress tensor [PITH_FULL_IMAGE:figures/full_fig_p026_19.png] view at source ↗
Figure 20
Figure 20. Figure 20: Starting of phase development as contour plot over four time steps n = [500, [PITH_FULL_IMAGE:figures/full_fig_p026_20.png] view at source ↗
Figure 21
Figure 21. Figure 21: Results of a plate with circular hole at one Gaussian point, showing graphs [PITH_FULL_IMAGE:figures/full_fig_p027_21.png] view at source ↗
read the original abstract

The compaction mechanisms of SiO2 glass under pressure include under certain conditions a specific reduction of the elastic moduli and a complex inelastic behavior whose nature is not yet fully understood. In our work we establish a variational framework describing the evolution of SiO2 glass under hydrostatic pressure. Based on a previous work that presents a model for multi-phase transformations in inelastic materials, we assume isothermal conditions during a compaction process and interpret the typical sigmoidal stress response as indicator of a binary phase transformation. During the process, two volume fractions coexist macroscopically and microstructures such as shear bands or disclination pattern develop in between. We restrict our approach to resolve only the volume fractions, not the corresponding microstructures. Nevertheless, the resulting model is shown to match experimental findings very well. Numerical examples successfully illustrate the relationship between the changes in the elastic moduli and the corresponding change in volume with respect to pressure.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript develops a variational framework for the evolution of SiO2 glass under hydrostatic pressure by extending a prior multi-phase transformation model. It assumes strictly isothermal conditions and treats the observed sigmoidal stress response as direct evidence of a binary phase transformation in which two volume fractions coexist macroscopically. The approach solves only for these volume fractions (not microstructures) and claims that the resulting model matches experimental compaction data well, while numerical examples illustrate the coupling between changes in elastic moduli and volume with respect to pressure.

Significance. If the binary-phase and isothermal assumptions hold, the work would supply a thermodynamically consistent variational description of compaction that directly links modulus reduction to evolving volume fractions. The numerical demonstration of this modulus-volume relationship is a concrete strength. However, the significance remains conditional because the central claim of good experimental agreement rests on an unverified modeling choice whose support is not shown through equations, data, or error metrics.

major comments (2)
  1. [Abstract] Abstract: the claim that 'the resulting model is shown to match experimental findings very well' is load-bearing for the paper's contribution, yet the abstract (and available text) supplies neither the governing equations, the experimental data sets, error bars, nor any quantitative comparison that would allow assessment of the match.
  2. [Abstract] Modeling assumptions (as stated in the abstract): the interpretation of the sigmoidal hydrostatic response as an indicator of binary isothermal phase transformation is the foundational modeling step; without additional justification, comparison to alternative mechanisms (distributed defects, mild thermal excursions), or independent experimental confirmation of the binary character, the variational construction risks solving an ill-posed problem even if its numerics are stable.
minor comments (1)
  1. The explicit restriction to volume fractions (rather than microstructures) is stated but could be accompanied by a brief discussion of how this truncation still permits prediction of the observed modulus-volume coupling.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments. Below we respond point by point to the major comments, indicating planned revisions where appropriate.

read point-by-point responses
  1. Referee: [Abstract] Abstract: the claim that 'the resulting model is shown to match experimental findings very well' is load-bearing for the paper's contribution, yet the abstract (and available text) supplies neither the governing equations, the experimental data sets, error bars, nor any quantitative comparison that would allow assessment of the match.

    Authors: The abstract summarizes the principal result. The governing equations appear in Section 2, where the variational framework is extended from the cited prior multi-phase model. Experimental data sets for SiO2 compaction under hydrostatic pressure are introduced in Section 3, and quantitative comparisons (volume change, elastic moduli evolution, and error metrics) are reported in Section 4 together with Figures 5–7 and Table 2. To improve accessibility we will revise the abstract to add a brief clause referencing these sections and the reported agreement. revision: yes

  2. Referee: [Abstract] Modeling assumptions (as stated in the abstract): the interpretation of the sigmoidal hydrostatic response as an indicator of binary isothermal phase transformation is the foundational modeling step; without additional justification, comparison to alternative mechanisms (distributed defects, mild thermal excursions), or independent experimental confirmation of the binary character, the variational construction risks solving an ill-posed problem even if its numerics are stable.

    Authors: The binary-phase and isothermal assumptions are stated explicitly and rest on two elements: (i) the sigmoidal shape of the hydrostatic stress–strain curve, which is widely interpreted in the SiO2 literature as macroscopic two-phase coexistence, and (ii) the direct extension of the thermodynamically consistent multi-phase variational model developed in our earlier work. The present formulation solves only for the volume fractions, not the microstructures, and the numerical results demonstrate that the resulting modulus–volume coupling reproduces the experimental trends. While alternative mechanisms such as distributed defects remain possible, the binary model supplies a variational structure that is consistent with the observed data. We will add a short paragraph in the introduction that justifies the modeling choice, cites supporting experimental interpretations, and briefly notes alternative mechanisms with references. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation relies on external experimental validation

full rationale

The paper explicitly adopts a modeling assumption (isothermal binary phase transformation to explain sigmoidal response) drawn from a prior framework and restricts itself to volume fractions, then demonstrates that the resulting variational model matches experimental compaction data. No quoted equation or step reduces a claimed prediction or result to its own inputs by construction. The self-citation to the multi-phase model supplies the variational structure but does not substitute for the independent experimental matching reported in the abstract. This is the normal case of a modeling paper whose central claim is tested against external benchmarks rather than being definitionally forced.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

Review performed on abstract alone; full equations, parameter lists, and derivation steps unavailable, so ledger entries are limited to those explicitly named in the abstract.

axioms (2)
  • domain assumption Isothermal conditions during compaction process
    Explicitly stated assumption used to simplify the variational setup.
  • ad hoc to paper Sigmoidal stress response indicates binary phase transformation
    Interpretation adopted to map the observed macroscopic response onto a two-phase model.

pith-pipeline@v0.9.1-grok · 5681 in / 1316 out tokens · 19613 ms · 2026-06-26T19:01:45.579387+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

44 extracted references · 24 canonical work pages

  1. [1]

    Mysen, P

    B. Mysen, P. Richet, Chapter 5 - silica, in: B. Mysen, P. Richet (Eds.), SilicateGlassesandMelts(SecondEdition), secondeditioned., Elsevier, 2019, pp. 143–183. URL:https://www.sciencedirect.com/science/ article/pii/B9780444637086000053

  2. [2]

    Trachenko, M

    K. Trachenko, M. T. Dove, Compressibility, kinetics, and phase tran- sition in pressurized amorphous silica, Phys. Rev. B 67 (2003) 064107. URL:https://link.aps.org/doi/10.1103/PhysRevB.67.064107

  3. [3]

    O. B. Tsiok, V. V. Brazhkin, A. G. Lyapin, L. G. Khvostantsev, Log- arithmic kinetics of the amorphous-amorphous transformations in SiO2 and GeO2 glasses under high pressure, Phys. Rev. Lett. 80 (1998) 999–

  4. [4]

    URL:https://link.aps.org/doi/10.1103/PhysRevLett.80. 999

  5. [5]

    Deschamps, J

    T. Deschamps, J. Margueritat, C. Martinet, A. Mermet, B. Cham- pagnon, Elastic moduli of permanently densified silica glasses, Scientific reports 4 (2014) 7193. doi:10.1038/srep07193

  6. [6]

    Petitgirard, C

    S. Petitgirard, C. Sahle, C. Weis, K. Gilmore, G. Spiekermann, J. Tse, M.Wilke, C.Cavallari, V.Cerantola, C.Sternemann, Magmaproperties at deep earth’s conditions from electronic structure of silica 9 (2019) 32–

  7. [7]

    doi:10.7185/geochemlet.1902

  8. [8]

    J. Du, A. Cormack, The medium range structure of sodium silicate glasses: a molecular dynamics simulation, Journal of Non-Crystalline Solids 349 (2004) 66–79. URL:https://www.sciencedirect.com/ science/article/pii/S0022309304007963, glass Science for High Technology. 16th University Conference on Glass Science. 28

  9. [9]

    Molnár, P

    G. Molnár, P. Ganster, A. Tanguy, E. Barthel, G. Kermouche, Densi- fication dependent yield criteria for sodium silicate glasses – an atom- istic simulation approach, Acta Materialia 111 (2016) 129–137. URL: https://www.sciencedirect.com/science/article/pii/S1359645 416302154

  10. [10]

    Huang, J

    L. Huang, J. Kieffer, Amorphous-amorphous transitions in silica glass. i. reversible transitions and thermomechanical anomalies, Phys. Rev. B 69 (2004) 224203. URL:https://link.aps.org/doi/10.1103/PhysR evB.69.224203

  11. [11]

    Parallelization of 3d mpdata algorithm using many graphics processors,

    F. Liebau, Structural Chemistry of Silicates, Springer Berlin, Heidel- berg, 1985. URL:https://link.springer.com/book/10.1007/978-3 -642-50076-3

  12. [12]

    Pabst, E

    W. Pabst, E. Gregorova, Elastic properties of silica polymorphs - a review, Ceramics - Silikaty 57 (2013) 167–184. URL:https://www.ce ramics-silikaty.cz/2013/pdf/2013_03_167.pdf

  13. [13]

    Huang, J

    L. Huang, J. Kieffer, Molecular dynamics study of cristobalite silica using a charge transfer three-body potential: Phase transformation and structural disorder, The Journal of Chemical Physics 118 (2003) 1487–

  14. [14]

    URL:https://doi.org/10.1063/1.1529684

  15. [15]

    L. P. Dávila, M.-J. Caturla, A. Kubota, B. Sadigh, T. Díaz de la Rubia, J. F. Shackelford, S. H. Risbud, S. H. Garofalini, Transformations in the medium-range order of fused silica under high pressure, Phys. Rev. Lett. 91 (2003) 205501. URL:https://link.aps.org/doi/10.1103/P hysRevLett.91.205501

  16. [16]

    Deschamps, C

    T. Deschamps, C. Martinet, D. de Ligny, B. Champagnon, Elastic anomalous behavior of silica glass under high-pressure: In-situ raman study, Journal of Non-Crystalline Solids 355 (2009) 1095–1098. URL: https://www.sciencedirect.com/science/article/pii/S0022309 309001926, siO2, Advanced Dielectrics and Related Devices

  17. [17]

    Bruns, T

    S. Bruns, T. Uesbeck, S. Fuhrmann, M. Tarrago, L. Wondraczek, D. De Ligny, K. Durst, Indentation densification of fused silica assessed by raman spectroscopy and constitutive finite element analysis, Journal of the American Ceramic Society 103 (2020). doi:10.1111/jace.17024

  18. [18]

    Keryvin, J.-X

    V. Keryvin, J.-X. Meng, S. Gicquel, J.-P. Guin, L. Charleux, J.-C. Sanglebœuf, P. Pilvin, T. Rouxel, G. Le Quilliec, Constitutive modeling 29 of the densification process in silica glass under hydrostatic compression, Acta Materialia 62 (2014) 250–257. URL:https://www.sciencedirec t.com/science/article/pii/S1359645413007520

  19. [19]

    de Ligny, T

    C.Sonneville, A.Mermet, B.Champagnon, C.Martinet, J.Margueritat, D. de Ligny, T. Deschamps, F. Balima, Progressive transformations of silica glass upon densification, The Journal of Chemical Physics 137 (2012) 124505. URL:https://doi.org/10.1063/1.4754601

  20. [20]

    Rouxel, H

    T. Rouxel, H. Ji, T. Hammouda, A. Moréac, Poisson’s ratio and the densification of glass under high pressure, Phys. Rev. Lett. 100 (2008) 225501. URL:https://link.aps.org/doi/10.1103/PhysRevLett.1 00.225501

  21. [21]

    C. Li, L. Zhang, L. Sun, C. Wu, D. Duan, Q. Lin, J. Ding, Z. Jiang, A finite element study on the effects of densification on fused silica underindentation, CeramicsInternational46(2020)26861–26870.URL: https://www.sciencedirect.com/science/article/pii/S0272884 220321751

  22. [22]

    Schill, S

    W. Schill, S. Heyden, S. Conti, M. Ortiz, The anomalous yield behavior of fused silica glass, Journal of the Mechanics and Physics of Solids 113 (2018) 105–125. URL:https://www.sciencedirect.com/science/ar ticle/pii/S0022509617309158

  23. [23]

    H. Wolf, D. König, T. Triantafyllidis, Experimental investigation of shear band patterns in granular material, Journal of Structural Geology 25 (2003) 1229–1240. URL:https://www.sciencedirect.com/scienc e/article/pii/S0191814102001633

  24. [24]

    Dinkelacker-Steinhoff, K

    S. Dinkelacker-Steinhoff, K. Hackl, A general model of microstruc- ture evolution including phase transformation in elasto-plastic mate- rials, PAMM 24 (2024) e202400024. URL:https://onlinelibrary. wiley.com/doi/abs/10.1002/pamm.202400024

  25. [25]

    Dinkelacker-Steinhoff, K

    S. Dinkelacker-Steinhoff, K. Hackl, A variational multi-phase model for elastoplastic materials with microstructure evolution, 2026. URL:http s://arxiv.org/abs/2602.17492.arXiv:2602.17492

  26. [26]

    Ortiz, L

    M. Ortiz, L. Stainier, The variational formulation of viscoplastic con- stitutive updates, Comput. Methods Appl. Mech. Eng. 171 (1999) 419– 444. 30

  27. [27]

    Mielke, Energetic formulation of multiplicative elasto-plasticity using dissipation distances, Contin

    A. Mielke, Energetic formulation of multiplicative elasto-plasticity using dissipation distances, Contin. Mech. Thermodyn. 15 (2003) 351–382. URL:https://doi.org/10.1007/s00161-003-0120-x. doi:10.1007/ s00161-003-0120-x

  28. [28]

    Miehe, M

    C. Miehe, M. Lambrecht, Analysis of microstructure development in shearbands by energy relaxation of incremental stress potentials: large- strain theory for standard dissipative solids, Internat. J. Numer. Meth- ods Engrg. 58 (2003) 1–41. URL:http://dx.doi.org/10.1002/nme.7

  29. [29]

    Miehe, M

    C. Miehe, M. Lambrecht, E. Gürses, Analysis of material instabilities in inelastic solids by incremental energy minimization and relaxation methods: evolvingdeformationmicrostructuresinfiniteplasticity, Jour- nal of the Mechanics and Physics of Solids 52 (2004) 2725–2769. URL: https://www.sciencedirect.com/science/article/pii/S0022509 60400105X. doi:https...

  30. [30]

    Kochmann, K

    D. Kochmann, K. Hackl, The evolution of laminates in finite crystal plasticity: a variational approach, Continuum Mech. Therm. 23 (2011) 63–85

  31. [31]

    Govindjee, K

    S. Govindjee, K. Hackl, R. Heinen, An upper bound to the free energy of mixing by twin-compatible lamination forn-variant martensitic phase transformations, Contin. Mech. Thermodyn. 18 (2007) 443–453

  32. [32]

    Waimann, P

    J. Waimann, P. Junker, K. Hackl, A coupled dissipation functional for modeling the functional fatigue in polycrystalline shape memory alloys, Eur. J. Mech. Solids 55 (2016) 110–121

  33. [33]

    F. Behr, G. Dolzmann, K. Hackl, G. Jezdan, Analytical and numerical relaxation results for models in soil mechanics, Continuum Mechanics and Thermodynamics 35 (2023) 1–23. doi:10.1007/s00161-023-01225 -9

  34. [34]

    M. S. Khan, K. Hackl, Modeling of Microstructures in a Cosserat Continuum Using Relaxed Energies: Analytical and Numerical As- pects, Springer International Publishing, Cham, 2021, pp. 57–87. URL: https://doi.org/10.1007/978-3-030-90051-9_3. doi:10.1007/97 8-3-030-90051-9_3

  35. [35]

    Hackl, F

    K. Hackl, F. D. Fischer, G. A. Zickler, J. Svoboda, Are onsager’s recip- rocal relations necessary to apply thermodynamic extremal principles?, 31 Journal of the Mechanics and Physics of Solids 135 (2020) 103780. URL: https://www.sciencedirect.com/science/article/pii/S0022509 619306878. doi:https://doi.org/10.1016/j.jmps.2019.103780

  36. [36]

    Hackl, F

    K. Hackl, F. Fischer, J. Svoboda, On the treatment of non-reciprocal rate-independent kinetics via thermodynamic extremal principles, Jour- nal of the Mechanics and Physics of Solids 145 (2020) 104149. URL: https://www.sciencedirect.com/science/article/pii/S0022509 620303823. doi:https://doi.org/10.1016/j.jmps.2020.104149

  37. [37]

    Kermouche, E

    G. Kermouche, E. Barthel, D. Vandembroucq, P. Dubujet, Mechanical modeling of indentation-induced densification in amorphous silica, Acta Materialia 56 (2008). doi:10.1016/j.actamat.2008.03.010

  38. [38]

    F. Birch, Finite strain isotherm and velocities for single-crystal and polycrystalline nacl at high pressures and 300°k, Journal of Geophysical Research: Solid Earth 83 (1978) 1257–1268. URL:https://agupubs. onlinelibrary.wiley.com/doi/abs/10.1029/JB083iB03p01257. doi:https://doi.org/10.1029/JB083iB03p01257

  39. [39]

    Mielke, Deriving new evolution equations for microstructures via relaxation of variational incremental problems, Comput

    A. Mielke, Deriving new evolution equations for microstructures via relaxation of variational incremental problems, Comput. Methods Appl. Mech. Engreg. 193 (2004) 5095–5127

  40. [40]

    Wang, The elastic properties, elastic models and elastic perspectives of metallic glasses, Progress in Materials Science 57 (2012)

    W. Wang, The elastic properties, elastic models and elastic perspectives of metallic glasses, Progress in Materials Science 57 (2012). doi:10.101 6/j.pmatsci.2011.07.001

  41. [41]

    Merklein, I

    M. Merklein, I. V. Kabakova, A. Zarifi, B. J. Eggleton, 100 years of brillouin scattering: Historical and future perspectives, Applied Physics Reviews 9 (2022) 041306. URL:https://doi.org/10.1063/5.009548 8

  42. [42]

    Grimsditch, Experimental studies of elastic properties of crystals by brillouin scattering, Physica B+C 150 (1988) 271–275

    M. Grimsditch, Experimental studies of elastic properties of crystals by brillouin scattering, Physica B+C 150 (1988) 271–275. URL:https:// www.sciencedirect.com/science/article/pii/0378436388901325

  43. [43]

    116.233901

    C. Weigel, A. Polian, M. Kint, B. Rufflé, M. Foret, R. Vacher, Vitreous silica distends in helium gas: Acoustic versus static compressibilities, Physical review letters 109 (2012) 245504. doi:10.1103/PhysRevLett. 109.245504. 32

  44. [44]

    C.-s. Zha, R. J. Hemley, H.-k. Mao, T. S. Duffy, C. Meade, Acoustic velocities and refractive index of SiO2 glass to 57.5 gpa by brillouin scattering, Phys. Rev. B 50 (1994) 13105–13112. URL:https://link .aps.org/doi/10.1103/PhysRevB.50.13105. 33