THE INFRARED TRANSMISSION SPECTRA OF 4 SILICATE-GLASSES BEFORE AND AFTER EXPOSURE TO WATER

The infrared transmission spectra of four silicate glasses were investigated. By using blown glass films, 1-2 μm thick, detailed infrared transmission spectra were generated over the 4000-180 cm−1 range, both before and after the films were exposed to water. The water had little effect on the spectra of the 70SiO2-20Na2O-10Al2O3 (mol %) and Pyrex compositions, but had a large effect on the spectra of the 70SiO2-30Na2O (mol %) and Corning 015 compositions. The Si-O nonbridged stretching band at ∼950 cm-1 and a largely overlooked bending band at ∼600 cm−1 were the bands most sensitive to hydration in the 70/30 and 015 compositions. Changes were also seen in the Si-O-Si bridged stretching bands at ∼1050 cm−1 and ∼770 cm−1. The water, however, had no effect on the dominant Si-O-Si bending band at 460 cm−1. It was also discovered that the 70/30 and 015 films reacted with the atmosphere to form a carbonate layer on their surface. This carbonate accounted for the 1450 cm−1 and 230 cm−1 bands seen in their infrared transmission spectra. © 1990, Materials Research Society. All rights reserved.