Optical Properties according to BaO Addition for BaO-GeO2-La2O3-ZnO System

초록

In this study, Barium Germanium glasses were prepared with a composition of xBaO-(72-x)GeO2-8La(2)O(3)-20ZnO where x = 16.0, 18.0, 20.0, 22.0 and 24.0 mol% respectively. Their physical and optical properties, such as refractiveness index, glass transition temperature (Tg), softening temperature (Ts), transmittance and Knoop hardness were studied. The results showed that refractive index, Tg, Ts and coefficient of thermal expansion (CTE) increased with increasing BaO concentration. The refractive index of all the prepared samples was observed between 1.7811 to 1.7881. The Abbe number was calculated by formula using nd (589.3 nm), nf (656.3 nm) and nc (486.1 nm) and observed to be between 38 to 40. The Abbe number of the prepared sample was similar to that of BaO and GeO2. The transmittance of the prepared glasses was observed to be between 80 similar to 82 % throughout the range from 200 nm to 800 nm. Knoop hardness divided into seven steps were measured 5 class (>= 450 similar to < 550) of all prepared samples.

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