STRUCTURE AND OPTICAL CONDUCTIVITY OF SILVER THIOGERMANATE GLASSES

Silver thiogermanate glasses xAgI . (I - x)[yAg2S - (1 - y)GeS2] were investigated by infrared reflectance and Raman spectroscopies to study the glass structure as a function of Ag2S (0 less-than-or-equal-to y less-than-or-equal-to 0. 5) and AgI (y = 0. 5, 0 less-than-or-equal-to x less-than-or-equal-to 0.375) content. The results for binary glasse s indicate that addition of Ag2S to GeS2 glass induces the depolymeriz ation of the thiogermanate network by creation of terminal Ge-S- bonds . AgI was also found to affect the network structure and this was expr essed by disproportionation reactions. The interactions between Ag+ io ns and their sites were also investigated and discussed in relation to the high ionic conductivity of these glasses. Broad range conductivit y spectra were also obtained by combining dielectric and far-infrared conductivity data. (C) 1994 Academic Press, Inc.