Firstly, the results of a three-component modified exponential decay fit to NR and SBR vulcanizates at different weathering durations are partially presented in Figure . To recall, the rigid-limit coupling corresponds to a 𝑇 2,𝑟 𝑒𝑓𝑓 of about 20 µs, which can be assigned to the highly constrained fraction. With a shape parameter (βr) fixed to 2, the amount of this rigid fraction (fr)