Glass reacts to temperature changes through expansion and contraction, with typical float glass expanding approximately 0.8mm per meter with each 100°F temperature increase. When heated or cooled unevenly, thermal stress develops between expanding and contracting areas, potentially causing breakage when stress exceeds the material’s strength—a phenomenon called thermal shock. Different glass types have varying coefficients of thermal expansion, with borosilicate glass (like Pyrex) offering superior thermal shock resistance compared to standard soda-lime glass. Tempered glass withstands temperature differentials up to 250°F, while annealed glass may break with just 100°F difference across its surface. In architectural applications, proper edge quality significantly impacts thermal stress resistance, with polished edges performing better than cut edges. Designers must consider expansion/contraction rates when specifying glass for environments with significant temperature fluctuations, using thermal breaks and flexible sealants to accommodate movement.
