Energetics of pressure-induced densification in GeO2 glass

The enthalpy of compaction of permanently densified GeO2 glass has been measured by HF solution calorimetry. For samples compressed under nonhydrostatic conditions up to 21 GPa, the relative compaction of 15% observed is associated with an excess enthalpy of 18 kJ/mol with respect to the 1-bar glass. The magnitude of the effect is similar to those reported at lower pressures for SiO2, but higher than for alkali silicate and albite glasses quenched from the melt at high pressure.