Role of WO3 in structural and optical properties of WO3–Al2O3–PbO–B2O3 glasses

Glass samples of composition xAl2O3--20PbO--(80-x)B2O3 and xWO3--xAl2O3--20PbO--(80-2x)B2O3 with x varying from 0% to 10% mole fraction are prepared by melt quench technique. The optical band gap decreases (from 3.21 to 2.37 eV) more for WO3--Al2O3--PbO--B2O3 glasses with an addition of WO3 content. The FTIR spectral studies have pointed out the conversion of structural units of BO3 to BO4 and WO4 to WO6 in these glasses. The increase in density from 4.51 to 5.80 g cm-3 for WO3--Al2O3--PbO--B2O3 glasses is observed with an increase in WO3 content. This is observed that the atomic structure changes more with the incorporation of WO3. This is due to the formation of WO6, WO4 and BO4 units.