The crystallization behaviour was investigated for some glasses within the system spodumene-orthoclase, during different heat treatments by DTA, XRD and SEM. Kaolin a and quartz sand were used as starting materials for the glass preparation and melting. The base glasses were stable through the heat treatments and did not show any crystallisation propensity, whereas TiO2 additions catalyze the crystallization tendency in the glasses. The crystallization process involved the formation of b-spodumene and leucite in addition to the metastable high quartz, which disappeared at higher temperatures. Translucent glass-ceramics, containing uniform and non- uniform microstructures, were obtained in the case of domination of high quartz and b-spodumene, respectively. Little difference in the coefficient of thermal expansion was noted in the base glasses.
