FTIR spectra and thermal properties of TiO2-doped iron phosphate glasses

• The increase in TiO2 content strengthen phosphate network chains.
• TiO2 link to phosphate unit through POTi bonds.
• Q0 formed at expense of Q1 and Q2 increase with increment of TiO2 content.

Structure and thermal properties of xTiO2·(90 − x) (60P2O5–40Fe2O3)⋅10CaF2 (x = 0, 5, 10, 15, 20 and 25 mol%) glasses are investigated in detail by Fourier Transform Infrared Spectrum (FTIR) and Differential Thermal Analysis (DTA), respectively. It is found that incorporation of TiO2 increase the density and glass transition temperature of iron phosphate system glass. The increment of doped-TiO2 can also strengthen phosphate network chains due to increasing O/P ratios and more orthophosphate (Q0) units formed in the glass structure at expense of pyrophosphate (Q1) units and metaphosphate (Q2) groups. Moreover, the structure of iron phosphate glass with TiO2 content contain distorted octahedral [TiO6] linked to phosphate unit through POTi bonds, thus enhanced structure cohesion and increased density obtained. The knowledge provides an improved understanding of the role of TiO2 in the structure of iron phosphate glasses.