Crystallization effect after preliminary heat treatment in MgOAl2O3SiO2 quenched glass

The effect of preliminary heat treatment (PT) of a quenched glass in the vitrification temperature range on the course of subsequent non-catalyzed crystallization is studied using the X-ray and pycnometer density measurements for glassy stoichiometric cordierite powder. An increase of crystallized μ-cordierite quantity after PT is found. It is established that this effect is caused by the ≈20% lowering of the activation energy of μ-phase formation due to the structural relaxation process taking place in quenched glass during PT. A qualitative model to explain the effect observed as a result of an interaction between defects in the initial quenched glass is proposed.