Raman Spectroscopy of SiO2Glass at High Pressure

Abstract
A new technique has been developed for optical studies of amorphous solids to very high pressures. Raman spectra of SiO2 glass measured at 8 GPa indicate a significant reduction in the width of the Si-O-Si angle distribution, which has been associated with a number of anomalous properties of silica glass under ambient conditions. Between 8 and ∼ 30 GPa irreversible changes in the Raman spectrum occur that are consistent with a shift in ring statistics in densified glass. The spectra suggest a breakdown in intermediate-range order at higher pressure.