The Effect of Immersion in a Buffered Base on the Optical Properties and Microhardness of Fluorozirconate Glasses

Abstract

Two ZrF4—BaF2—LaF3—AIF3 (ZBLA) and four ZrF4—BaF2—YF3—AIF3 (ZBYA) glasses were immersed in a buffered base at 25°C for several days. They were then examined using an IR spectrophotometer in order to determine the effect on the optical properties, and a microhardness tester for surface degradation. The ZrF4 content in these compositions ranged from 44 mol% to 57 mol%. IR analysis showed that the amount of hydroxyl and H2O penetration was dependent upon the concentration of ZrF4 in the glass. The IR characteristics of ZBYA—1, which contained 44 mol% ZrF4, did not appear to be affected by the aqueous environment, while ZBLA—20, which contained 57 mol% ZrF4, showed the presence of a large amount of hydroxyl and H2O. The base immersion did not appear to strongly affect the microhardness of the compositions.