Role of MgO on the HAp forming ability in phosphate based glasses

Phosphate-based glasses 45P2O5–30CaO–(25 − x)Na2O–xMgO for different compositions of x = 0, 1, 2.5, 5 and 10 mol% were prepared using the normal melt quench technique. To study the influence of MgO on phosphate glasses, a series of experimental analyses such as ultrasonic velocities, differential thermal analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy, pH measurements, Fourier transform infrared spectroscopy, scanning electron microscopy and in vitro studies were carried out in all the prepared glasses. A maxima in ultrasonic parameters at x = 2.5 mol% of MgO content and a further decrease in the same with the addition of MgO content were observed in all glasses. The observed results indicate that structural compactness of glass network took place up to 2.5 mol% of MgO (PCNM2.5), beyond which a loose packing of atoms led to structural softening in glass network. The results obtained from X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy analyses in all glasses before and after in vitro studies revealed the existence of higher HAp-forming ability in PCNM2.5 glass.