The structural dual role of Fe2O3 in some lead-phosphate glasses

The FT-IR study of iron concentration effect on the xFe2O3·(1 − x)[2P2O5PbO] glass system with 0 ≤ x ≤ 50 mol% has revealed the dual role of Fe2O3 both as network modifier and former. The addition of iron oxide leads to more PO bond breakage and the formation of the P–O–Fe bonds. We concluded that at high content of Fe2O3 it acts in the structure of glasses as a network former. The presence of the Fe–O–P bonds for higher content of iron oxide in this glass system is consistent with the improving of their chemical durability. The appearance of these types of bonds and others structural units for Fe2O3–P2O5–PbO glasses are investigated by FT-IR spectroscopy.