Crystal growth and structural relaxation in lead metasilicate glass

Abstract

The understanding of the glass state at temperatures below glass transition temperature (Tg) is one of the greatest challenges for material science researchers. In this work we will study the Kauzmann paradox, which is far below the glass transition temperature, from point of view of the relaxation and crystallization kinetics. For this we will get experimental data of viscosity, refraction index, specific heat and crystal growth rates from a single batch of lead metasilicate glass (PbO.SiO2). Afterwards, the experimental data will analyzed with aid standard models of the crystallization, viscosity and relaxation at temperatures around Tg and extrapolate until the Kauzmann temperature. From this analysis, we intend to verify that the paradox occurs or not.Furthermore, a new method will be tested to obtain the crystals growth rates via Differential Scanning Calorimetry (DSC). Our research group developed this new technic and it was tested only once with lithium disilicate glass. It will be a great opportunity to verify the efficiency of this new method since crystal growth rates will be obtained by two different techniques, DSC and microscopic analysis, using samples from the same batch.