¹⁹F NMR studies of barium fluorozirconate glasses containing alkali metal fluorides

¹⁹F FT-NMR spectra of ZrF₄{single bond}BaF₂-based glasses containing LiF, NaF and CsF are examined as a function of temperature. The degree of motional narrowing observed over the temperature range 298-420 K as a function of composition correlates strongly with the glass transition temperature and with previous conductivity and transport number measurements. Varying the alkali metal content results in minima of fluoride ion mobility at 10-20 mol% LiF and ∼ 20 mol% NaF, and to a lesser extent on Li/Na mixing.