Polymerization processes are very complex and high nonlinear. Their modeling often involves reaction mechanism analysis combined with empirical tests. Mismatch between the model and the industrial plant often exists and it can be the cause of bad performance when optimal input profiles computed for a particular model are applied to the actual plant. The approach followed in this paper is to directly modify the input profile from batch to batch, and it has been applied through computer simulations to the determination of the minimum-time temperature profile for the batch bulk polymerization of sqrene under modeling error. The results demonstrate that the approach has strong robustness characteristics and fast convergence properties.