Structural aspects of calcium iron phosphate glass containing neodymium oxide

• Nd2O3CaOFe2O3P2O5 glass was investigated by hardness, infrared and Raman spectra.
• Homogeneous glasses were obtained within 10 mol% Nd2O3 additions.
• Hardness showed that Nd2O3 strengthened the crosslinking of the glass network.
• PONd bonds enter the pyrophosphate structure by replacing Q1 terminal oxygen.

Homogeneous glasses of the xNd2O3(100 − x)(12CaO20Fe2O368P2O5) system were obtained within the 0 ⩽ x ⩽ 10 mol% composition range. The density and molar volume measurements helped to understand the structural changes occurring in these glasses. Vickers-hardness results showed that addition of Nd2O3 strengthened the crosslinking of the glass network. Spectra analysis indicated that Nd2O3 enters in the structure of the phosphate glasses as a network modifier. The depolymerization of the glass network by the addition of Nd2O3 is characterized by the increase in the concentration of pyrophosphate. The decrease of the Q1 terminal oxygen with increasing Nd2O3 content indicated that PONd bonds participated in the pyrophosphate glass structure, determined from the Raman spectra.