INFRARED SPECTROSCOPIC ANALYSIS OF WATER INCORPORATED IN THE STRUCTURE OF INDUSTRIAL SODA-LIME-SILICA GLASSES

The paper illustrates a method for the determination of the water cont ent of glasses by infrared transmittance spectroscopy from the extinct ions of the bands due to free and hydrogen-bonded hydroxyl groups diss olved in the glass. The procedure is discussed in detail, highlighting the sources of random and systematic errors and what can be done to i mprove the interlaboratory reproducibility. The ratio of the intensiti es of the two bands at 2.8 and 3.6 mu m is investigated accurately for a range of industrial soda-lime-silica glasses. In the case of contai ners and float glass it is nearly constant, but it varies widely for o ther products, such as household appliances, car headlamps and hand-wo rked articles, probably due to differences in the glass formulation. A ccordingly, caution should be exerted in using the simplified method b ased on the measurement of the first band only, implying a constant ra tio. Finally, evidence of molecular water in the dealkalized surface l ayers of commercial articles is obtained using infrared reflectance sp ectroscopy.