Digital Polarized Stress Analyzer for Glass Bottles: Test Methods

A digital polarized stress analyzer for glass bottles is used to evaluate residual stress in glass products in accordance with GB/T4545. The SWY-I digital glass stress analyzer operates on the principle of polarized light interference to examine internal stress in glass or birefringence in crystals. Equipped with a sensitive tint plate and employing a quarter-wave (1/4 λ) compensation method, the instrument supports both qualitative and semi-quantitative assessments based on interference color orders in the polarized field. It also enables accurate quantitative measurement of internal stress values. This makes it suitable for optical instrument manufacturers, glass plants, glassware producers, and laboratories measuring stress in optical glass, glass products, and other optical materials. Test methods: 1) Qualitative method: Determine whether internal stress is present. 2) Quantitative method: Determine the magnitude of stress. Switch on the instrument. Without a sample, the entire field of view appears dark brown. Insert the sample and, without rotating the analyzer (inspection polarizer), locate the brightest point in the field of view; this corresponds to the maximum stress location. Then rotate the analyzer’s graduated dial until the brightest point turns dark brown again. Record the rotation angle on the dial and the thickness at that point. Use the appropriate formula to convert these readings into a stress value. Results can be displayed automatically and printed.

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