Résumé
In this study we present the results of nanoindentation and isostatic compression simulations of sodium borosilicate glasses using Molecular Dynamics, alongside experimental results obtained by Raman spectroscopy. For nanoindentation, three glasses with varying sodium content were simulated both in their pristine form, as well as a “disordered” one, which is analogous to the real irradiated glass and exhibits a swollen and more depolymerized network. The results indicate a very low increase of coordination of the silicon atoms, in contrast to boron and sodium. Densification occurs by the decrease of free volume and takes place in regions rich in glass formers. On the contrary, we observed evidence of high shear flow around sodium atoms. In the compression simulations, the pristine forms of the glasses were brought to a pressure of 20 GPa and then decompressed again. We found that the amount of free volume has a major influence on the amount of densification, alongside the percentage of three-coordinated boron. At the same time, sodium creates soft regions in the glass that can be more easily compressed. The results are then compared to Raman spectra collected on the imprint marks of experimentally indented borosilicate glasses.