Intercomparison of IR transmittance measurements on water-containing glasses : Report of the International Commissionon Glass (ICG) Technical Committee14 "Gases in Glass"

Abstract

A previous paper illustrated a procedure recommended by Technical Committee 14 (TC 14 "Gases in Glass") of the International Commission on Glass (ICG) for the determination of the water content of soda-lime-silica glasses by infrared transmittance spec-troscopy. The present paper describes the results of an intercomparison of spectral transmittance measurements performed by TC 14 in order to check the interlaboratory reproducibility that can reasonably be expected when a range of industrial laboratories determines the water content of a given sample. Three samples were circulated within a group of 10 laboratories and for each of them17 spectral transmittance curves were reported, using various spectrophotometers. From each spectrum the corresponding water content value was calculated, using the TC 14 procedure. A statistical elaboration of the results is presented. The spectral transmittance values were affected by a significant spread, with maximum relative deviations up to 14.4 % (maximum relative standard deviation 4.5 %).The spread affecting the corresponding calculated water contents was much smaller, with maximum relative deviations within 4.8 % (maximum relative standard deviation 1.3 %).