Structural, optical and bioactive properties of calcium borosilicate glasses

Glass of composition 40SiO2–20B2O3–30CaO–10M2O3 (M = Al, Cr, Y and La) were prepared by the splat quenching technique to investigate the effect of M2O3 on their bioactivity, structural and optical properties. Y2O3 and Cr2O3 containing glasses formed a crystalline hydroxyapatite (HA) layer after dipping in simulating body fluid (SBF) for 25 days. On the other hand, HA layer could not form in Al2O3 and La2O3 glasses. However, during soaking in SBF solution, these glasses exhibit higher dissolution rate, lower density and increased optical band gap as compared to unsoaked glasses. Their oxygen molar volume was also higher than for Y2O3 and Cr2O3 glasses. The change in composition affects the cross-link formation in the glass matrix and finally its durability and bioactivity in SBF. The results show that M2O3 plays an important role in controlling chemical durability and bioactivity of the glasses.