Glasses were studied by using 19F nuclear magnetic resonance methods. The activation energy for F-ion migration in ZrF4-36BaF2-3LaF3-4mol%AlF3 was equal to 0.42eV for temperatures of between 127 and 230C.

P.J.Bray, D.E.Hintenlang, R.V.Mulkern, S.G.Greenbaum, D.C.Tran, M.Drexhage: Journal of Non-Crystalline Solids, 1983, 56[1-3], 27-32