Formation and properties of rare earth galliogermanate and aluminogermanate glasses

The density, glass transformation temperature and hardness of these glasses increase with increasing atomic number and concentration of the rare earth ion present in the glass, while the thermal expansion coefficient is independent of rare earth identity. Glasses containing alumina are less dense and have lower refractive indices and thermal expansion coefficients than those containing gallia, but they are also more refractory and harder. The magnetic susceptibility and Verdet coefficients of these glasses are consistent with other studies of glasses containing various rare earth ions. These glasses exhibit excellent chemical durabilities in water.