Focussed on coupled mechanical (flow), thermal and geometrical conditions, the emphasis of the present work is laid on the influence of shear flow through rheological measurements. The rheological properties measurement has often been used to follow the development of crystallization, both in quiescent conditions and under shear. One can cite: van Puyvelve et al. [1] with the RheoDSC device (combination of the rheological and calorimetric signal), Roozemond et al. [2] with the RheoDSC in the study of flow-induced crystallization through short-term shear flow experiments, Pantani et al. [3] with the rotational Haake Mars rheometer equipped with an optical module. The present investigation used the same rheo-optical RheoScope module (Thermo Scientific)*. The discussions deal with the correlation between the strong increase (crystallization) or decrease (melting) in viscosity and the transformed fraction and the morphology (spherulites and oriented structures) development or vanishing, which were determined simultaneously. The characteristic features of the crystallization process have been quantified (i) number of activated nuclei, (ii) spherulite growth, (iii) overall kinetics. A discrimination of the contributions from spherulitic morphology and oriented structures on the viscoelastic functions of an isotactic polypropylene is done. Acknowledgement The authors kindly acknowledge Florent Jego and Philippe Sierro (Thermo Fisher Scientific) for their technical support with RheoScope module. [1] Janssens V., Block C., van Assche G., van Mele B., van Puyvelde P., Intern. Polym. Proc. 25, 304-310 (2010) [2] Roozemond P. C., van Drongelen M., Verbelen L., van Puyvelde P., Peters G.W.M., Rheol. Acta 54, 1-8 (2015) [3] Pantani R., Speranza V., Titomanlio G., J. Rheol. 59, 377-390 (2015)