CHARACTERIZATION AND X-RAY PHOTOELECTRON-SPECTROSCOPY INVESTIGATION OF PBO-BI2O3-GA2O3 GLASSES

XPS O1s spectra were recorded for glasses in the binary PbO-Ga2O3 and ternary PbO-Bi2O3-Ga2O3 systems. Large shoulders with chemical shifts of 1.4 to 1.9 eV were observed in the O1s spectra recorded from PbO-Ga2O3 glasses. These shoulders were attributed to the presence of nonbridging oxygens in the structure. The shoulders indicated that, contrary to previous results, PbO was a network modifier as well as a charge compensator and network former. The addition of Bi2O3 reduced the number of nonbridging oxygens and, therefore, it was classified as an intermediate. Ga2O3 seemed to form GaO4- tetrahedra, constituting the backbone of the network structure. Glasses in the PbO-Bi2O3-Ga2O3 system had their IR cutoff edges located at 7 mu m with glass transition temperatures in the range of 320 degrees to 400 degrees C.