The glass cooling rate during molding process has significant effect on the crystallization behavior and structural uniformity of Al₂O₃-SiO₂-Na₂O-CaF₂ oxyfluoride glass-ceramics. Abaqus Finite Element Analysis indicated that at room temperature cooling environment, the cooling rate of 8mm thick glass was notably lower than that of 3 mm thick glass. The interior temperature of 8 mm thick precursor glass was still above 710 ^oC even after the sample was cooled for 15 s, which caused the formation of “crystal stones” in precursor glass. The microstructure of oxyfluoride glass and glass-ceramics with different thickness was analyzed by using DTA, XRD, IR and SEM. Since the 8 mm thick glass was cooled slowly, the initial crystal nucleation generated in the interior of glass, mixed crystal phases were formed in the interior after heat treatment, while single CaF₂ crystal phase formed on the surface. On the contrary, there was only uniform CaF₂ crystal phase generating in the 3 mm thick precursor glass after heat treatment, as a result of high cooling rate during molding process. Besides, the mechanism and ways to optimize the structure uniformity of glass ceramics were also be discussed

Keywords: Oxyfluoride glass-ceramics, Finite element analysis, Cooling rate, Microstructure