Raman spectra of indented pristine and irradiated sodium borosilicate glasses

In this work we have carried out variable-load indentation testing on three sodium borosilicate glasses and characterized the indentation imprints using Raman spectroscopy. The resulting analysis of the spectra helps towards the description of the relative amount of densification and shear flow appearing in each glass, as well as the different microstructural mechanisms that take place during deformation. Additionally, we show that the two glasses that are relatively poor in sodium exhibit enhanced mixing of the silicate and borate subnetworks after indentation. For the indentations performed using the highest load, we have also acquired spectra by focusing at various depths below the imprint, in order to characterize the deformed region of the glasses and estimate its size. Similar experiments have been also carried out for one of the three glasses after neutron irradiation, in order to study the effects of mechanical deformation on its depolymerized and swollen structure.