Traditional photoelasticity premits only qualitative estimation of stress in glass articles of complicated shape. Errors in peak stresses may be manyfold. Manufacturing of resistant glass articles demands accurate knowledge of the residual stresses in order to optimize the glass manufacturing technology.
Laboratory of Photoelasticity has 40 years of experience in measuring stress in glass articles, especially in articles of complicated shape. For that Laboratory has developed modern measurement technology as well as automatic polariscopes which are easy to handle and can be used in the vicinity of the production line.
For measuring stresses in axisymmetric glass articles a new method, based on integrated photoelasticity has been developed. The method permits the determination of the distribution of all the stress components in solid and hollow glassware. Regions with highest stress can be easily found. The method has been successfully used for measuring stresses in drinking glasses, bottles, neck tubes of the CRT glass bulbs, lamps, optical fibre preforms, etc., for many companies. New projects concern development of photoelastic tomography for stress measurement in glass articles of arbitrary shape and of a portable scattered light polariscope for thickness stress measurement in flat glass.