Covalent Bond Scission in the Mullins Effect of a Filled Elastomer: Real‐Time Visualization with Mechanoluminescence

Strain‐induced light emission from mechanoluminescent cross‐linkers in silica‐filled poly(dimethylsiloxane) demonstrates that covalent bond scission contributes significantly to irreversible stress‐softening upon the initial extension, known as the Mullins effect. The cross‐linkers contain dioxetanes that emit light upon force‐induced bond scission. The filled elastomer emits light in cyclic uniaxial tension, but only on exceeding the previous...