Influence of the modifying cations on physical properties of fluorozirconate glasses

The structure of ZrF4-based glasses is still poorly understood. The addition of compounds such as BaF2 and NaF to ZrF4 breaks up the Zr-F-Zr network (such as it exists in β-ZrF4), creating new bonds and changing the physical properties of the material. Although both Ba2+ and Na+ cations play the role of traditional glass modifiers, they affect certain physical properties in a different way. A structural model previously proposed for a typical ZBLAN fluorozirconate glass composition is able to explain the effect of the substitution of Na+ for Ba2+ cations, in glasses with the same overall degree of modification.