A study was made of the conductivity relaxation of glasses in the system, ZrF4-BaF2-YF3-NaF (with 5 to 30mol%NaF) at 10Hz to 2MHz, and from 300K to just below the glass transition temperature. It was found that the conductivity decreased with increasing NaF content, and resulted from a decreasing decoupling of the F- ions from the viscous motion of the glassy network. Small values of the stretching exponent were observed, and were associated with a high cooperation between the F- ions in the conductivity relaxation process.

Conductivity Relaxation in ZrF4-BaF2-YF3-NaF Glasses. M.Sural, A.Ghosh: Journal of Physics - Condensed Matter, 1999, 11[16], 3315-22