<p>Modelling crystallization under stretch is a key topic for fatigue design of rubber-like antivibration parts. Nevertheless, most of the academic studies consider unfilled natural rubber while the industrial materials are fully formulated compounds filled with carbon blacks and exhibit a highly dissipative visco-elastic behavior. This behavior is very useful for antivibration systems but complicates the characterization and modelling of the phase change, as the addition of fillers and additives brings in numerous additional dissipation sources and intricates the time effects on the thermomechanical response and on crystallization. In this study, we use wellresolved WAXD synchrotron measurements to perform in situ measurements under various mechanical protocols. The objective is to characterize the evolution of the triplet {strain, stress, crystallinity index}, and their derivatives, for various time and mechanical solicitations. First, classic load/unload tension tests over a range of strain rates leading to non-equilibrium cases are achieved, to serve as a reference database on the compound studied. Then, a multi-relaxation cyclic test combining static and monotonic steps is applied in order to describe the crystallization state and kinetics around a relaxed state (sometimes called “equilibrium hysteresis”). The results provide a precious database to identify or challenge the existing thermodynamic models, for conditions seldom met in the literature: fully formulated material and various mechanical loading time histories. </p>