Crystallization of lithium disilicate glass using high frequency microwave processing

Crystallization of lithium disilicate (LS₂) glass using 30GHz microwave processing was investigated. Glass frit was used as the starting material to prepare the glass via the regular melt-quench method. The annealed glass was investigated using X-ray diffraction (XRD) and thermal analysis to ensure the glassy structure formation and to determine the nucleation and the crystallization temperatures. The glass samples were first nucleated conventionally before they were crystallized using microwaves. Characterization of the glass-ceramics was performed using XRD and scanning electron microscopy. The 30GHz microwave processing was successfully used to crystallize LS₂ glass without the aid of susceptors in a relatively short time at lower temperature compared to conventional heating. The result of this experimental investigation was in close match with the theoretical calculations that were done based on the molecular orbital model of microwave absorption. The microwave absorption in LS₂ glass was highly dependent on the microwave frequency.