In-situ Raman spectral characterization of sodium borosilicate glasses at high temperatures

In-situ Raman spectra were studied for sodium borosilicate glasses containing large amounts of boron oxide as functions of temperature and holding time. Such characterization enabled the determination of the changes 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 decreased in concentration as these glasses were heated through melted temperatures as was noted earlier for boroxol groups involving only three-coordinated boron ions in pure boron-silicate compositions.