Journal of Non-Crystalline Solids 55 (1983) 125-130 125 North-Holland Publishing Company STUDY OF SODIUM SILICATE MELT AND GLASS BY INFRARED REFLECTANCE SPECTROSCOPY Florent DOMINE * and Bernard PIRIOU Laboratoire des Elbments de Transition dans les Solides, C.N.R.S., 92190 Meudon- Bellevue, France Received 15 October 1982 Infrared reflectance spectra and the derived absorption spectra of a Na20-1.41 SiO 2 glass and of the parent melt are reported. Polymers with 2 bridging oxygens per silicon (chains) and 3 bridging oxygens (sheets) are identified. Spectra of glass and melt are qualitatively similar. Melt absorption bands show a 10-30 cm- i shift to lower frequencies. They are broader and less intense than those of the glass which does not agree with Sweet and White's reflectance measurements on similar glass and melt. The small differences between glass and melt can be attributed to the thermal expansion of the medium. 1. Introduction Information concerning silicate melt structures has been difficult to acquire due to experimental problems. As a result, melt structures have usually been extrapolated from a knowledge of glass structure. The purpose of this study is to compare spectra of a silicate glass and of the parent melt in order to verify these extrapolations. Comparisons of Raman spectra at room temperature and high temperature have already been performed by Piriou and Arashi [1] on SiO2-PbO glasses and melts, by Seifert et al. [2] on Na20-AI203-SiO 2 glasses and melts. These authors conclude that the same structural units occur both in glasses and melts. A comparison of the infrared reflectance spectra of Na20-SiO 2 glasses and melts have also been performed by Sweet and White [3], but the frequency range over which their studies were carried out is narrower than in the present study, and their quantitative data were different from those reported in this paper. 2. Experimental The sample studied was prepared from high purity SiO 2 and Na2CO 3. The approximate sample composition was made by weighing the dried components * Present address: Laboratoire de Ghologie, Ecole normale sup4rieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France. 0022-3093/8"~/01300-0000/~na nn ~ i o~a ~,~r,h_~,,ll,,A