glasses were prepared by a melting-quenching method. The glass
electrical conductivity was investigated by both electrochemical impedance spectroscopy at different
temperatures from 283 K to 333 K and four-probe method at room temperature (293 K). Meanwhile,
as a major factor determining the electrical conductivity of a solid, optical band gap was also studied.
By comparing the electrical conductivity values and glass optical band gap evolution, it was found that
(GeTe4)100xAgx glasses are mainly electronic conductive. On the other hand, the electrical conductivities
of (GeTe4)100x(AgI)x glasses firstly show a monotonic decrease by increasing AgI up to 15 mol.%, and then
an increase when the AgI content is higher than 15 mol.%. The activation energy Ea and the pre-exponential
factor r0 show apparent turning point when AgI content is 15 mol.%, signifying a conductivity mechanism
change. In this paper, correlations between the conductivity and hypothetical structures in
(GeTe4)100xAgx and (GeTe4)100x(AgI)x glasses are done and the importance of the Ag role is underlined.