Effect of pressure on the structural stability of iron phosphate glass: Role of trace water

Raman and infrared spectroscopic measurements were carried out on 40 mol% Fe₂O₃:60 mol% P₂O₅ iron phosphate glass samples to study the effect of increasing external pressure on the local structure of both anhydrous and water trapped glasses. In-situ high‐pressure Raman measurements, done up to 24.2 GPa on anhydrous samples, revealed hardening of the phonon modes accompanied by a loss of Raman intensity and ultimately leading to complete smearing of modes at very high pressures. These changes were found to be reversible upon quenching the sample back to ambient pressure. Raman and infrared spectroscopy of pressure quenched IPG samples containing trace amounts of water have revealed definite signatures of devitrification at room temperature.