The ionic conductivity and permittivity of glasses based on ZrF4, BaF2, LaF3, AlF3 and NaF (ZBLAN) or PbF2, InF3, BaF2, AlF3 and LaF3 (PIBAL) are studied. The influence of the glass composition on the glass transition temperature (T-g) and on the crystallization temperature (T,) is reported. For all ZBLAN glasses the temperature dependencies of the ionic conductivity are close one to another (sigma(500) = 8(2) (.) 10(-6) S/cm) and their conduction activation enthalpies are equal to 0.82(1) eV. From the point of view of the ionic conductivity, the best glass compositions are the PIBAL50 (50 m/o PbF2) and PIB45 (45 m/o PbF2).