Effect of ZnO and Al2O3 ِAddition on the Physical Properties of Cobalt Doped Phosphate Glass

Glass system of chemical composition 49.5 P2O5– (30-X) ZnO–XAl3O2 -20Na2O-0.5 CoO with (X= 0, 2,5,7.5 and 10 mole%) hase been prepared by melt quenching technique. The amorphous nature was confirmed by X-ray diffraction (XRD).
The density has been measured using Archimedes method the density (ρ) and molar volume Mv follow apposite trend. The density decreases (ρ) while molar volume (Mv) increase with increasing Al content. This is most likely due to the difference in molecular weights of ZnO and Al2O3.
Using optical absorption, the optical band gap energy has been determined and was found to decrease with increasing Al2O3 content on the other hand Urbach energy (∆E) increases, by increasing Al2O3.
Cobalt behave as band pass filters. The characterized parameters of these filters.i.e. area, center, width and height of band pass, have been estimated. The crystal field (Dq) and the Racah parameters (B) were evaluated.