Production and investigation of black glasses as absorber materials: Transition metal ions doped silicate glasses

A 60% SiO2-20% Na2O-18% CaO-2% Al2O3 glass structure was prepared and 20 wt% CoO was incorporated to this base glass to produce black glass by melt-quench technique. The effects of transition metal ions on the physical, thermal and optical properties of the black glass were investigated as V2O5 and CuO were doped to its structure. The density values of the glasses range from 2.59 g cm−3 to 2.89 g cm−3. As the doping ratio of transition metal ions increased, the glass transition temperature (Tg) values increased but the melting temperatures (Tm) did not show this regular change. The thermal stability and glass forming ability values of all glasses were also calculated. The absorption spectra of glasses were taken in the wavelength range 200-1100 nm. The values of optical band gap energy were determined from Mott and Davis's model. The refractive index values were calculated with the help of the optical band gap results by use of the Dimitrov-Sakka relation. Optical dielectric constants were also calculated by using the refractive index values. All results were elucidated with regard to the structural changes obtained effect of the transition metal ions. The variation in physical, thermal and optical properties was related to the non-bridging oxygen change in the structure.