Paper Title
A Study on the Nanometer Scale Crystallization Mechanism and Photoluminescence Characteristics of B2O3-Al2O3-CaF2 : Eu Glass

In this study, crystallization glass containing CaF2-Al2O3-B2O3: Eu2O3 (hereinafter referred to as CAB: Eu) glass was controlled to produce calcium difluoride crystal phase. The crystal structure and optical properties of the sample were evaluated by DTA, XRD, SEM, and photoluminescence(PL) spectrometer. CAB mother glass had a glass transition temperature (Tg) of 557.1℃, a glass softening point (Ts) of 638.5℃, and a crystallization maximum ratetemperature (Tp) of 831.4℃. In this study, heat treatment was performed at 680 ~ 820℃, which is lower than Tp, in order to induce nano-scale crystallization and to inhibit excessive crystal growth. Eu-doped parent glass produced CaF2 crystal at a higher temperature than Eu-free glass and a PL-independent Al5BO9 phase was formed at 800 ℃ or higher. The CAB crystal glass samples showed a high value of PL intensity at 613 nm when given a wavelength of 395 nm. In addition, the maximum PL strength was appeared at the heat treatment condition of 780°C and 4 hours within a range of 760 to 820°C and 0 to 16 hours. In this study, we confirmed the relationship between the crystal structure, microstructure, and photoluminescence properties of crystallized glass with CaF2 crystal phase and confirmed that it can be applied to transparent ceramic materials requiring red color in the future. Keywords - Oxy Fluoride Glass, CaF2, Nanometer Crystal, Photoluminescence, Eu-Doping, Crystallization