Elucidation of the crystallization kinetics for sodium-alumino-silicate glasses containing different amounts of manganese oxide

Abstract

The glass samples [40SiO2 + 5Al2O3 + {55 − x}Na2O + xMnO2] where x = 0.05, 0.2, 0.4, 0.6, 0.8, and 1 mol% MnO2 before and after being heat treated were subjected to X-ray diffraction. The diffraction lines provided clear evidence of the nucleation and growth, which are characteristic of sodium silicate phase. Crystallization studies were conducted using differential thermal analysis. Crystallization peak temperatures were identified and the transformed fractions were determined. Both the rate of growth, K 0, and the activation energy, E, depend on the influence of manganese ions in the glass network as a modifier or as a former and the manganese content. The values of the Avrami parameter, n, were calculated using two methods and were in excellent agreement. The process of nucleation and growth rate depends on the manganese content.