The structures of glasses in this system were investigated by means of infra-red, Raman and X-ray absorption spectroscopy. In the case of orthophosphate compositions, Ga was found in 4-fold coordination whereas, in metaphosphate glass, the coordination was 6-fold. In the case of pyro-, tri- and tetraphosphate glasses, the Ga atoms were distributed on tetrahedral and octahedral sites. The Ga atoms on octahedral sites were expected to be chelated by pyrophosphate groups. The ionic conductivity was deduced from complex impedance diagrams. It was found that this conductivity increased rapidly with the Na content. At 150C, the conductivity increased by a factor of 100 when the molar fraction of Na was doubled. On the other hand, for a given value of the Na molar fraction, the conductivity did not seem to be very sensitive to the structure of the glassy network.

P.Berthet, E.Bretey, J.Berthon, F.D’Yvoire, A.Belkebir, A.Rulmont, B.Gilbert: Solid State Ionics, 1994, 70-71, 476-81