Effect of high pressure in the Li2O–2SiO2 crystallization

The aim of this work was to investigate the effect of previous treatments at high pressures on the crystallization kinetics of monolithic samples of a Li2O–2SiO2 (LS2) glass. The glass transition temperature (Tg) and the temperature of the onset of crystallization (Tp) obtained by differential thermal analyses (DTA) were measured for LS2 glass samples submitted to isostatic pressures ranging from 2.5 to 7.7 GPa during 5 min at room temperature. The observed systematic changes in Tg and Tp were probably related to the cracks induced by high pressure inside the monolithic samples and in its surface. Away from the cracks, the nucleation density slightly decreased as a function of pressure but along the cracks, the nucleation density was significantly higher.