First stages of the crystallization in fluorozirconate glasses

The effect of long heat treatments on the ZBA fluorozirconate glass (BaF2, ZrF4, AlF3) at a temperature close to the glass transition (Tg) was studied. The crystallization of ß-BaZrF6 was detected by Raman scattering in transparent samples after heating for 400 h at 310°C. A Porod regime in SAXS was observed after the same heat treatment. Raman scattering and fluorescence of Pr3+ ions showed a continuous modification of the glass during the heat treatment. This observation is in agreement with continuous decomposition of the glass before crystallization.