Structural properties of iron containing calcium-magnesium borophosphate glasses

• Structure and bioactivity of the Fe2O3–P2O5–CaO–MgO–B2O3 system were studied.
• XRD, FTIR and ESR studies showed changes both in phosphate and iron environments.
• Bioactivity tests indicated that iron free sample showed some bioactivity.
• Crystallization tendency increased with increasing iron concentration.

The glass system xFe2O3⋅(55 − x)P2O5⋅30CaO⋅5MgO⋅10B2O3 has been prepared for x = 0–15. Structural characterizations of as casted and heat treated samples were highlighted by means of X-ray diffraction, infrared and electron spin resonance spectroscopies. Effects of iron addition on the phosphate network have been identified by new bands observed in the 400–1150 cm−1 wavenumber range in the infrared spectra. Electron spin resonance spectra showed the iron ions ligand field effect through resonances centered at g ≈ 4.3 and g ≈ 2.0. There were discernable changes in the electron spin resonance spectra after the heat treatment. The samples were tested for bioactivity in simulated body fluids for 15 and 30 days. No evidence of bioactivity was found in the infrared spectra after 15 days immersion in simulated body fluid while three hydroxyapatite markers have been identified in the infrared spectrum of the iron free sample after 30 days immersion in simulated body fluid.