Effect of Cr2O3 concentration on physical and optical properties of sodium barium bismuth silicate glasses

Abstract

 Cr2O3 doped sodium barium bismuth silicate glasses have chemical composition (30-x)SiO2 : 30Na2O : 10 Bi2O3 : 30BaO : xCr2O3 where x is 0.0, 0.1, 0.3, 0.5, 0.7 and 1.0 mol% and characterized physical and optical properties. The densities of Cr2O3 doped glasses were increase due to the result of molecular weight of glasses. On the hand, the molar volumes of glasses were decreased. The refractive indexes also increased which vary by densities. The absorption result, the spectra of Cr2O3 doped glasses appear broadband around 630 and 690 nm in an octahedral site due to Cr3+ ions which corresponding to 4A2 → 4T2 and 4A2 → 2T1 transition, respectively by Tanabe-Sukano diagram. Nevertheless, the absorbance decreased with Cr2O3 concentration since Cr3+ may be transfer electron. The optical band gaps were studied with Urbach plot. It found that Cr2O3 concentration at 1.0 mol% shows the maximum optical band gap value.