Effect of CuO on the structure and properties of (50−x/2)Na2OxCuO(50−x/2)P2O5 glasses

(50−x/2)Na2OxCuO(50−x/2)P2O5 glasses (5≤x≤33.33) have been synthesized and investigated by Fourier transform infrared (FT-IR) and Raman spectroscopies. FT-IR and Raman spectral investigations reveal the formation of POCu bonds and show the evolution of the phosphate skeleton: (PO3)∞ chains for NaPO3 to P2O74− groups in the richest CuO glass. The formation of POCu bonds increases the cross-link density in the glass network and therefore increases Tg of the glasses. The improvement in chemical durability with increasing CuO addition is attributed to the replacement of POP bonds in the glass by more hydratation resistant POCu bonds and to the strong cross-linking of the phosphate chains by the copper ions.