FTIR and physical features of Al2O3–La2O3–P2O5–PbO glasses

Glasses in the quaternary system La2O3–PbO–Al2O3–P2O5 were prepared and their structures were studied by FTIR. The variations of the structural groups within the glass matrix were followed by the determination of the area and frequency of each band of FTIR spectra. The analysis of the FTIR spectra revealed that the former role of Al2O3 controls the short-range order of the glasses. The physical parameters such as the density, the dimensionality and the elastic moduli of the phosphate network are sensitive to the concentration of Al2O3. The elastic moduli were calculated in terms of Makishima–Mackenzie model. The results of the density and the elastic moduli were interpreted in terms of the vibrations of aluminates and phosphate structural units and the replacement of low bond strength PbO by high bond strength Al2O3.