Characterization of copper doped phosphate glasses for optical applications

The phosphate glass system of chemical composition 42P2O542ZnO(16−x)Na2O(x)Cu2O with (x=0, 2, 4, 6, and 8) has been prepared by the conventional glass melt technique. The effect of copper content on density and molar volume has been investigated. It was found that the density of the glass increases with increasing copper content. This can be accounted by the difference between the atomic weights of copper and sodium. The estimated values of molar volume follow the common pattern where it exhibits opposite trend to that of density. The optical absorption has been measured from 200 to 900 nm. While absorption is observed only in the UV range for the base glass, a well defined absorption band has been observed in the visible region, the width of which increases by increasing copper content. With higher copper content another band starts to appear in the IR range. The refractive index has been estimated according to the Clausius–Mossotti method using the ionic refraction. The obtained values of refractive index have been used in estimating some characteristic features such as elasto-optic coefficient and susceptibility. The results reveal the importance of such glass composition in optical filter applications.