Structure-property correlation in (50 −x)Na2O–50P2O5–xCoCl2 glassy systems

Abstract Ternary sodium–cobalt–phosphate glasses of the composition (50 − x )Na 2 O–50P 2 O 5 – x CoCl 2 with x varying between 0 and 15 mol% prepared by melt quenching have been characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) techniques. Thermal ( T g , T c ) and electrical properties have been investigated. Infrared spectra reveal the formation of metaphosphate glasses ( Q 2 tetrahedral units) with symmetric bridging oxygen (P–O–P) and non-bridging oxygen (P–O − ). The spectra also indicate the formation of P–O–Co bonds in the metaphosphate glasses that replace P–O − –Na + bonds. The results of thermal studies correlate with these FT-IR findings and support the formation of P–O–Co bonds and an increased cross-link density with increasing CoCl 2 . This results in enhanced chemical durability and increased T g and T c of the glasses. The electrical conductivity parameters upon changing the composition have been correlated with structural changes in the glass matrix.