Effect of irradiation on some optical properties and density of lithium borate glass

Borates and silicate glasses containing boron oxide have been widely used for optical lenses with high refractive index and low dispersion characteristics. Alkali borate glasses are of great technological interest especially lithium borates as solid electrolytes because of their fast ionic conduction. In this study the optical properties including infrared and refractive index and density of lithium borate glass as a base glass were studied. The effect of the presence of either aluminum or lead oxide, or the presence of one of the following transition metal, Fe2O3, TiO2 or V2O5 was investigated. The effect of exposing the glass to either gamma, or fast neutron irradiation on the last properties was also studied. The results showed that three main bands appeared due to bending vibration or stretching of either, tetrahedral or triagonal borate units. The addition of alkalies causes only a shift of the bands either to higher or lower wavelength. Glass containing lead oxide had the highest refractive index and density, also the presence of any of the transition metal oxide lowering the average coordination number of oxygen which causes a compaction of the structure hence an increase in the values of density and refractive index. Since irradiation of glass causes compaction of B2O3 by breaking the bonds between triagonal elements, the average ring size becomes smaller which leads to an increase in density and refractive index too.