[Raman spectra analysis of calcium metaphosphate glass-ceramics]

In the present paper, calcium metaphosphate glass with molar ratio of Ca/P = 0.45 was prepared and Ca(PO3)2 glass-ceramics were obtained by reheating the glass at 300-700 degrees C. The Raman spectra of samples were measured. The bands of these Raman spectra were assigned and analyzed. The length of P-O bonds was calculated by using Raman wavenumbers. The results show that the crystal phase in glass was obtained when preserved at 300 degrees C for 3 h; Along with temperature increase, upsilon(s) (PO2) and upsilon(s) (POP) bands are stable in frequency, the bands intensity increases and fine structure appears in the Raman spectra fingerprint. The crystallization degree of glass-ceramics surface is higher than the inner. The length of P-O bonds changes during the heating process and crystallization. The length of O--P--O chain bonds changes to 158.27 pm from 159.96 pm, and terminal P--O changes to 149.02 pm from 147.92 pm, when Ca(PO3)2 glass becomes beta-Ca(PO3)2 crystal.