Experimental and theoretical studies of the structure of tellurate-borate glasses network

The structural properties of the xTeO₂·(1-x)B₂O₃ glasses (x = 0.6; 0.7) were investigated by FT-IR spectroscopy. From the analysis of the FTIR spectra, it is reasonable to assume that by the increasing of boron ions content, the tetrahedral BO₄] units are gradually replaced by the trigonal BO₃] units. The increase in the number of non-bridging oxygen atoms would decrease the connectivity of the glass network and will yield the depolymerization of the borate chains. The molecular structure and vibrational frequencies of the proposed structural models have been studied by exploring the density functional theory (DFT) calculations. The FTIR spectra of the xTeO₂·(1-x)B₂O₃ vitreous systems were compared with the calculated spectrum. This procedure allowed us to assign most of the observed IR bands.