Relationship between composition,density and refractive index for germania silica glasses

The density and the refractive index for various compositions of binary SiO₂GeO₂ glass prepared by a flame deposition technique, similar to that used to make low-loss optical waveguides, have been measured by standard Archimedes method and the Becke line method, respectively. The density as a function of composition is calculated considering the effective volume of the ions contained in the glass to be invariant. The refractive index as a function of composition is also calculated, based on the Lorenz-Lorenz equation, by computing the electronic polarizability of fused silica and germania. All calculated results are in good agreement with the observed data.