Physical, optical and structural studies of copper-doped lead oxychloro borate glasses

Bluish coloured glasses are obtained from the composition PbCl-PbO-BO doped with Cu ions. Basic physical properties and spectroscopic studies (optical absorption, electron paramagnetic resonance, Fourier transform infrared and Raman spectroscopies) were carried out on these samples. The increase in PbCl content resulted in the decrease in density and increase in molar volume. At optical frequencies, band gaps and Urbach energies were evaluated and their variation is explained. Spin-Hamiltonian parameters (SHP) obtained from the EPR spectra suggest that the ligand environment around Cu is tetragonally distorted octahedral sites and the orbital is the ground state. The characteristics broad bands in the optical absorption spectra are assigned to the BB transition. The bonding coefficient values were evaluated using optical data and SHP. FTIR studies suggested that the glass structure is built up of BO and BO units. The presence of diborate, pyroborate, pentaborate groups, etc. in the glass network was confirmed from Raman spectra.