Raman spectra study of iron phosphate glasses with sodium sulfate

Glasses with nominal molar composition of xNa2SO4–(1 − x)(0.4Fe2O3–0.6P2O5) (0 ⩽ x ⩽ 0.45) were prepared, and the structure of the glasses was investigated by Raman spectroscopy. No crystalline phases were detected by XRD in all samples. From the sodium sulfate-free iron phosphate glass, Q0 (in the Qn terminology, n represents the number of bridging oxygens (BO) per PO4 tetrahedron), Q1 and Q2 groups were observed. But the Raman spectra imply that Q1 groups are the predominant structural units. Addition Na2SO4 content result in the conversion of Q1 to Q0 groups, indicating that depolymerization of the phosphate network with the addition of Na2SO4 content. The bands of sulfate vibrational modes increase with addition higher Na2SO4 content, indicating that sulfate is incorporated into the glass matrix.