Determination of the OH content of glasses

Abstract

The most widely used method for determination of the OH content of glasses is the IR spectroscopy. The absorption bands in the range of 2500 to 4000 cm⁻¹ are due to the fundamental stretching vibrations of OH groups having different degrees of association. The calibration of the absorption coefficient, α, of an OH band requires the determination of the absolute OH content of some samples by another method than IR spectroscopy. Comparing water outgassing method with ¹H NMR spectroscopy, a large difference in the OH content was observed. Therefore, it is more appropriate to use solely the absorption coefficient as a relative measure of the true OH content. If certain requirements are met, the quantitative analysis of the absorption coefficient of different glass samples is justified.