The influence of potassium substitution for barium on the structure and property of silver-doped germano-gallate glasses

•Silver-doped germano-gallate glasses have been successfully synthesized.•Potassium substitution for barium leads to a glass network depolymerization with the apparition of non-bridging oxygens.•No change of the silver environment has been noted through the potassium substitution process.•The introduction of barium tends to stabilize the silver ions inside the glass matrix and to reduce the devitrification kinetics. The structure and crystallization of silver-doped germano-gallate glasses for substitution of potassium for barium ions have been investigated. By means of Raman spectroscopy, a structural study has been carried out revealing a glass network depolymerization with the formation of non-bridging oxygens likely localized on germanium tetrahedra when the barium concentration increases. These structural modifications do not appear to significatively change the silver ion environments or ionic states, as reported on luminescence and optical transmission spectroscopies. A combined differential scanning calorimetry, X-ray diffraction characterization, scanning electron microscopy and micro-luminescence spectroscopy demonstrate that the barium ions introduction tends to stabilize the silver ions and to influence drastically the devitrification and the crystal growth kinetics. Correlations have been established between ionic conductivity, silver distribution and crystal growth mechanisms.