Infrared spectroscopy of germanium dioxide (GeO₂) glass at high pressure

Room temperature infrared studies have been performed on GeO₂ glass under quasi-hydrostatic pressures of 9.5 GPa. The mid-infrared absorption spectrum of GeO₂ glass (g-GeO₂) shows two distinct vibrational modes, one at 560 cm^-1 (mid frequency peak) and another at 870 cm^-1 (high frequency peak). At pressures above 6 GPa, these two absorption peaks broaden and intensity in the region between them (∼700 cm^-1) increases dramatically. We interpret this change in the infrared spectrum at high pressure as the onset and progression of the amorphous to amorphous transformation from a low-density tetrahedral glass to a high density octahedral network glass.