SURFACE BEHAVIOR OF BIOACTIVE GLASS OF Si–Na–Ca–P SYSTEM IN SIMULATED BODY FLUID

Glass of the Si–Na–Ca–P system has been synthesized by normal melting and annealing technique. The obtained glass powders and annealed blocks were showed to be amorphous by X-ray diffraction (XRD). The thermal properties of glasses were analyzed by differential scanning calorimetry (DSC), it showed that the glass transformation temperature (Tg) was 556.3°C. The behavior of annealed glass discs in simulated body fluid solution (SBF) was studied in polyethylene containers at a constant temperature of 37°C for different time up to 14 days. The changes in the surface morphology and composition were observed by electronic probe microanalyzer (EPMA) associated with energy dispersive spectroscopy (EDS). Glass surface changed quickly as soon as immersion took place, and after longer soaking time, it showed different superimposed internal and external layers, which were identified as SiO2-rich and CaO–P2O5-rich layers, and on the external layer, spherical particles were also discovered.