Further studies on the IR spectra of silicate glasses

Abstract

Infrared spectra of the PbOSiO 2 glass system were studied by the KBr method. The absorption peaks show some different features as compared with the author's previous work on infrared spectra of alkali silicate glasses. It was found that with increasing PbO content the main absorption peak at a wave number larger than 1000 cm −1 originally shifts to less than 1000 cm −1 as the PbO content reaches 40 mol%; at the same composition occurs the abrupt change in property-composition curves of the PbOSiO 2 glass system. It is interesting that the absorption peak of non-bridging SiO links near 950 cm −1, being typical in the IR spectra of Na 2O·2SiO 2 glass, is rather weak in the spectra of Li 2O·2SiO 2 glass and almost disappears in that of PbO·2SiO 2 glass; this agrees with the different stability of the crystalline phase of corresponding bisilicate compounds. Infrared spectra of a series of Na 2OCaOSiO 2 glasses have also been studied. A new peak appears when the SiO 2 content is below 74 mol% and the glass composition enters the narrow region of commercial soda-lime glasses. As to K 2OPbOSiO 2 glasses, the shifting of the main absorption peak becomes obvious when the glass composition is near those of commercial glasses. Discussions have been given on different structural groups of SiO links adjacent with different metal ions. An attempt has been made to give some structural interpretations of the reason why the chemical compositions of commercial soda-lime and potash-lead silicate glasses are concentrated in a narrow region.