Structural, thermal and optical properties of phosphate glasses doped with SiO2

Abstract Glasses with a general formula (0.9-x)NaPO 3 -xSiO 2 -0.1ZnO (0 ≤ x ≤ 0.1 mol) have been prepared using the conventional melt-quenching technique. Samples were investigated by means of X-ray diffraction, density evolutions, refractive index measurements (n), differential scanning calorimetry (DSC), Fourier-transformed infrared (FTIR), Raman and UV-Visible spectroscopy. The variations of density and refractive index of the glass series were attributed to the structural changes of the glass network resulting from the incorporation of SiO 2 . The increase in glass transition temperature (T g ) values reflects an increase of the rigidity of the glass network when SiO 2 is gradually introduced. These results were correlated with FTIR and Raman investigations which revealed the enhancement of the vitreous network when P-O-P bonds were replaced by P-O-Si. The variation of the optical band gap (E opt ) of the amorphous materials indicated an increase in the band gap energy with the glass composition. This behavior can be explained by the increase of number of non-bridging oxygen (NBOs) which is probably due to the depolymerization of phosphate chains.