Structural variations of germanosilicate glasses with change in modifier cation type or Ge/Si ratio.

Raman spectroscopy was used to study glasses of three-component systems M2O-SiO2-GeO2, where M = Li, Na, K. Following the decomposition of spectra into component lines, the main structural units of both the germanate and silicate networks were determined according to peak-fitting result. With addition of germanium oxide, a change in the structure of the silicate network system was observed. In revealing highly-coordinated germanium atoms in all synthesised glasses, the study also established the dependence of their quantity on GeO2 content and modifier cation type.