Compositional Variation of ZBLAN Melts at High Temperature

Thermo gravimetric analysis (TGA) has been used to study the weight loss from a ZrF sub 4 -BaF sub 2- LaF sub 3 -AlF sub 3 -NaF glass forming between 700-900C. The composition of the condensed vapor has been determined at a number of different temperatures using atomic spectroscopy. Vapor pressures for each component have been determined and the implications for compositional control of glasses derived from such melts and the tailoring of physical properties including refractive index are discussed.