Physicochemical studies of phosphate based P2O5–Na2O–CaO–TiO2 glasses for biomedical applications

Glasses P2O5–Na2O–CaO–TiO2 with different TiO2 contents and fixed P2O5 (45 wt%) and CaO (24 wt%) have been prepared employing the normal melting and annealing technique. Measurements such as ultrasonic velocity, attenuation, solubility and pH have been carried out in all the compositions of the glasses. It is interesting to note that the above measured ultrasonic parameters exhibit an abnormal behavior (minimum) at 0.5 wt% of TiO2 content, beyond which an increase in these parameters with increasing TiO2 content is observed. The maximum pH values and Ca2+ ion release have been observed for the TiO2 free glass those compositions with and the low TiO2(⩽1.0 wt%) content. As the content of the TiO2 increases, the solubility of the glasses decreases. The observed weight loss reveals two stages of phosphate dissolution kinetics i.e. the first stage, in which the weight loss is proportional to t1/2, and a second stage in which a linear behavior is observed.