Structural and optical properties in gadolinium–aluminum–lead-germanate quaternary glasses

Glasses in the quaternary system 0.05Al2O3·0.95[xGd2O3·(100-x)(7GeO2·3PbO)] with 0 ≤ x ≤ 40 mol% have been prepared from melt quenching method. In this paper, we investigated structural and optical properties in gadolinium–alumino–lead-germanate glasses through investigations of FTIR (Fourier-Transform Infrared Spectroscopy) and UV–VIS (Ultra-Violet) spectroscopy. servations presented in these mechanisms show that by increasing Gd2O3 content up to 40 mol%, the glass network modification has taken place mainly in the germanate part, while the excess of oxygen can be accommodated in the host network by the creation of shorter rings of [Ge2O7] structural units and the formation of [AlO4] structural units. The affinity pronounced of the gadolinium cations towards germanate structural units produces the formation of the Gd2Ge2O7 crystalline phase. –VIS spectroscopy data show the charge transfer transitions of Pb+ 2–O− 2, Al+ 3–O− 2 and Gd+ 3–O− 2, respectively. The additional absorption in the range of 300 to 600 nm was attributed to other types of defects such as: non-bridging oxygen ions, change in valency of ions and other color centers. lues of the direct optical band gap of the glasses are determined from the optical absorption spectra. By increasing Gd2O3 content in the glass matrix, the optical band gap energy increases indicating changes of the lattice parameters by Gd2O3 incorporation.