Infrared spectroscopic analysis of water incorporated in the structure of industrial soda-lime-silica glasses

Abstract

The paper illustrates a method for the determination of the water content of glasses by infrared transmittance spectroscopy from the exdnctions of the bands due to free and hydrogen-bonded hydroxyl groups dissolved in the glass. The procedure is discussed in detail, highlighting the sources of random and systematic errors and what can be done to improve the interlaboratory reproducibihty. The ratio of the intensities of the two bands at 2.8 and 3.6 µm is investigated accurately for a range of industrial soda-lime-silica glasses. In the case of containers and float glass it is nearly constant, but it varies widely for other products, such as household appliances, car headlamps and hand worked arücles, probably due to differences in the glass formulation. Accordingly, caution should be exerted in using the simplified method based on the measurement of the first band only, implying a constant rado. Finally, evidence of molecular water in the dealkalized surface layers of commercial articles is obtained using infrared reflectance spectroscopy.