Provided herein are conductive glass-metal compositions, as well as methods of making and using such compositions. In one example, the compositions include gold (Au) doped lithium-borate glasses shown to exhibit a transition from ionic to electronic conduction within the same sample. This is achieved via appropriate heat treatment, and particularly by heat treatment after annealing, wherein the post-annealing heat treatment is performed at temperatures below the glass transition temperature (Tg). The methods described herein are believed to introducing polarons formed from the trapping of electrons at partially ionized gold atoms. This unique electrical response provides new functionality to this class of nanocomposites. Additionally, increased thermal conductivity can be provided to an otherwise low conductive glass composition using the inventive methods and other subject matter provided herein.