Abstract
A series of barium zinc borophosphate glasses doped with copper oxide was prepared for optical filters. The phosphate network exhibited P-O bonds in Q(1)-Q(2) modes. The ions of zinc and barium vibrated in distorted octahedral coordination, while the borate groups create the P-O-B linkage. Depending on the copper content, the glass exhibited bandpass filters in the ultraviolet (UV) region from 190 to 250 nm and the visible-near infrared (vis-NIR) region from 670 to 1400 nm. The Davis-Mott relation was used to deduce and mathematically prove the optical transition and transition order. The optical band gap (E-g) exhibited direct allowed transition, with values decreasing from 4.416 eV (base glass) to 2.511 eV (7% CuO). The refractive index (n(o)) and optical dielectric constant (e(o)) were deduced from the E-g. The glass density (r) was increased from 3.292 g/cm(3) (the base) to 3.5 g/cm(3) (7% CuO).