Crystallization kinetics in a 5BaO·8SiO2 glass

Abstract The accuracy of a Differential Thermal Analysis (DTA) technique for predicting the temperature range of significant nucleation is examined in a 5BaO·8SiO2 glass based on iterative numerical calculations. The diffusion coefficient is calculated from the measured induction time and the crystal growth velocity. The Classical Theory of Nucleation and the Diffuse Interface Theory were used to model crystal nucleation and growth. However, in both theories, two different diffusion coefficients were required for the calculated crystallization peaks to match the measured DTA data. The development of small nuclei near the critical size during nucleation was calculated using the diffusion coefficient from the measured induction time for nucleation. The growth of nuclei much larger than the critical size was determined by the diffusion coefficient from the measured growth velocity. The difference could reflect a complicated nucleation process in which the primary nucleating phase is not the 5BaO·8SiO2 crystal.