Crystallization and optical properties of a transparent mullite glass ceramic

Transparent mullite - based glass ceramics in the system SiO₂-Al₂O₃-B₂O₃-ZnO-K₂O were prepared. The activation energy of crystallization, the Avrami constants and the mechanism of crystallization of mullite were determined by the Matusita method through differential thermal analysis. X-ray diffraction and scanning electron microscopy methods were also used to determine the type and morphology of the precipitated crystalline phase. In addition, the degree of crystallinity was determined by the internal standard method. The results showed that bulk crystallization was the main mechanism for crystallization of the glasses. Optical absorption and photoluminescence properties of the obtained transparent glass-ceramics and their initial glasses were also studied. The glass-ceramics exhibited two emissions at 680 and 700 nm.