Chromium doped (80-x)Sb2O3-20K(2)O-xPbO glasses: Effects of PbO on the optical properties in Urbach's rule region

The optical absorption of Cr doped (80-x)Sb2O3-20K(2)O-xPbO glasses is measured in the spectral region 2,75-3,35 eV at room temperature. Optical band gap, Urbach energy and other physical parameters for different PbO concentrations are calculated and discussed. An interpretation of the obtained results is given in the frame of the Lattice Compatibility Theory (LCT).