IN-SITU RAMAN SPECTRAL CHARACTERIZATION OF SODIUM BOROSILICATE GLASSES AT HIGH-TEMPERATURES

In-situ Raman spectra were studied for sodium borosilicate glasses con taining large amounts of boron oxide as functions of temperature and h olding time. Such characterization enabled the determination of the ch anges in the nature of the molecular species that were present in the glasses and their melts after various treatments. The analysis of the spectral data indicated that boroxol rings involving one or more four- coordinated boron ions in the sodium oxide-containing glasses decrease d in concentration as these glasses were heated through melted tempera tures as was noted earlier for boroxol groups involving only three-coo rdinated boron ions in pure boronsilicate compositions.