FORMATION OF FLUOROZIRCONATE GLASSES UNDER HIGH-PRESSURES

Two ternary and one multicomponent fluorozirconate glasses have been p repared by melt quenching under pressures up to 25 kbar in a piston cy linder apparatus. Infrared and Raman spectra of these glasses were rec orded at ambient conditions and were similar to the corresponding spec tra of fluorozirconate glasses prepared at ambient pressure. However, a decrease in the frequency of an intense high frequency Raman band in dicated that the coordination number of zirconium had increased with i ncreasing quench pressure. In situ Raman spectra at pressures up to 90 kbar were recorded at ambient temperature using a diamond anvil cell. A reversible increase in the frequency of the strong Raman band was o bserved both for the glass quenched at ambient pressure and that forme d at 25 kbar. The initial rate of frequency increase was greater for t he high pressure glass, confirming that configurational changes had be en quenched in the sample prepared at high pressure.