Spectroscopic evidence of irreversible changes in cesium loaded iron phosphate glasses under pressure

• High pressure studies on cesium iron phosphate glasses done for the first time
• Disproportionation of iron phosphate glass with Cs incorporation
• Resilience of iron phosphate glass network against high external pressures
• Cesium induced irreversible densification upon high pressure exposure

Detailed Raman spectroscopic studies on 40:60 iron phosphate glasses (IPG) and cesium doped IPG under ambient conditions revealed an evident disproportionation of the pyrophosphate network beyond 18 mol% Cs doping. In situ high pressure Raman spectroscopic studies were carried out on IPG and Cs doped IPG up to 40 GPa for the first time in order to investigate the structural stability of these glasses under pressure. Although the parent glass is found to be robust to such high pressures, pressure quenched samples loaded with cesium beyond 18 mol% concentration were observed to permanently cross link leading to new high density forms of the glass. The extent of cross linking is observed to systematically increase with the cesium content in the parent matrix.