Effect of thermal treatment on physical properties of bioactive glass

The bioactive glass of composition 53SiO2–6Na2O–22CaO–11K2O–5MgO–2P2O5–1B2O3 (1–98) has been prepared using the melt method. The ultrasonic velocities, attenuation and elastic properties measurements have been made operated at a fundamental frequency of 5 MHz at room temperature on bioactive glass 1–98 before and after different thermal treatment conditions. Further, the frequency dependence of the attenuation was fitted into a linear relation α = afN. The observed linear increase in velocities, density and elastic properties of bioactive glass as a function of thermal treatment temperature, indicates that the densification in bioactive glass is due to the change in network bond per unit volume and not due to the structural/cross-linkage changes. Thus, thermal treatments of bioactive glasses lead to changes in elastic properties of bioactive glass. Furthermore, a long-term thermal treatment at higher temperatures also seemed to cause such changes to the glass surface that the formation of Ca,P-layer was inhibited during a 48 h immersion in simulated body fluid (SBF).