DIFFERENT PROCESSES FOR THE PREPARATION OF FLUOROZIRCONATE GLASSES

Different processes for the preparation of fluorozirconate glasses (ZBLAN) have been investigated by infrared spectroscopy (IR) and x-ray diffraction (XRD) on fluoride powders, during the reaction. Glasses have been prepared with 20-10-5-0 (% weight) ammonium bifluoride (NH4F·HF) or with nitrogen trifluoride (NF3) as fluorinating agent. In order to improve the quality of the glasses, small percentages (about 5%) of NH4F·HF are a good compromise between fluorination and hydration of starting products; NF3 is very effective during the fluorination step of the preparation: our electron spin resonance measurements (ESR) on these last glasses after γ-irradiation (20 Mrad), do not detect any O2 signal. © 1990.