Glass transition temperature and activation energy of sintering by optical dilatometry

A new possibility for measurements of glass transition point, fictive temperature and activation energy of viscous flow in the glass transition range is shown by using a contactless horizontal optical dilatometer and pressed powder samples. The results are compared with ones, obtained with bulk samples and traditional differential contact dilatometer.The possibility for a correct measurement of the activation energy of sintering, Еsin, is also highlighted by means of glasses with different compositions and various crystallization trends. In glasses with low crystallization trend Еsin decreases with the temperature rise in the whole sintering range; in glasses with higher crystallization ability, Еsin, starts anomaly to increase with the beginning of the phase formation. As a result, at low heating rates the densification is partially inhibited.