Effect of Y2O3 and La2O3 on structure and dielectric properties of aluminoborosilicate glasses

The aluminoborosilicate glass samples with substituting La2O3 for Y2O3 were prepared in order to obtain excellent dielectric properties. The samples were prepared by the conventional melting method. The structure, thermal properties and dielectric properties of the samples were investigated by FTIR, DSC and impedance instrument. It can be seen from IR curves that with the increasing of La2O3 (from 0.5 mol% to 3.0 mol%) the average number of bridging oxygen per tetrahedron first increased and then decreased. The DSC curves revealed that △T (△T = Tc − Tg, Tc and Tg represent the glass crystallization temperature and the glass transition temperature, respectively) first increased and then decreased. It is found that, the glass network structure reached the maximum degree of polymerization when the sample contain 1.5 mol% La2O3. Then continue to increase the content of La2O3 reduced the degree of polymerization. Dielectric constant (εr) and dielectric loss (tanα) decreased with the increasing of polymerization of the network structure. As a result, aluminoborosilicate glass with 1.5 mol% La2O3 and 1.5 mol% Y2O3 achieved the best structure and dielectric properties (εr = 4.67, tanα = 7.9 × 10−4).