Structural studies of boron and tellurium coordination in zinc borophosphate glasses by 11B MAS NMR and Raman spectroscopy Original Research Article

Zinc borophosphate glasses doped with TeO2 with different B2O3/P2O5 ratio were prepared, their basic properties were determined and their structure was studied by 11B MAS NMR and Raman spectroscopies. Structural studies were devoted to the investigation of changes in boron coordination in the dependence on changes in TeO2 content and in B2O3/P2O5 ratio in the borophosphate glasses. A special attention was devoted to the formation of mixed structural units B(OP)4−n(OTe)n in the studied borophosphate glasses, where by the deconvolution of 11B MAS NMR spectra quantitative data on the number of BO3 and B(OP)4−n(OTe)n mixed structural units were obtained. Raman spectra showed shortening of phosphate chains both with increasing TeO2 and B2O3 content. Raman spectra also showed that with the replacement of P2O5 by B2O3 in the studied glasses TeO4 units are replaced by TeO3 units as the number of oxygen atoms in the glass decreases when the B2O3/P2O5 ratio increases.