Raman scattering in silica glass in the permanent densification region

Abstract

Raman spectra of silica glasses were measured at pressures up to about 20 GPa. The bandwidth of a broad band in the region 300–500 cm−1 reduced and approached D1 observed at 495 cm−1 with increasing pressure. The change was reversible with compression up to about 10 GPa. Above 10 GPa, the D2 line was enhanced and the change in the 300–500 cm−1 band became irreversible. The resultant spectrum, which was that of densified silica glass, had fundamentally the same structure as that of normal silica glass, although each band was different from that in normal glass in bandwidth, relative intensity, and peak position. D1 and D2, which were the mode associated with intercluster layer or cluster surface, were dominant in Raman scattering in high density silica glass.