Frequency dependent conductivity of single alkali and mixed alkali phosphate glasses

The frequency dependent conductivity σ(f) of single alkali glasses LiPO3 and RbPO3 has been compared with the conductivity of the mixed alkali glass Li0.5Rb0.5PO3. The low frequency plateau value σ0 of the conductivity drops by several orders of magnitude in the mixed alkali glass. In this work the effect of mixed alkali on the shape of the conductivity σ(f) in the dispersive region has been analyzed. The slope of the conductivity curve, in the log σ vs. log f plot, increases more rapidly in the single alkali glasses than in the mixed composition. The onset of the dispersive region is more gradual in the mixed alkali glass. The results indicate that the mixed alkali glass behaves as a dilute single alkali glass.