A parameter estimation procedure was developed to fit a kinetic model with the experimental data obtained from methyl methacrylate (MMA) solution polymerization in a 10 L batch reader. For molecular weight control, we applied the modified two-step method in calculating the optimal temperature trajectory on the basis of the identified kinetic model. Application of a conventional proportional-integral (PI) controller to track the temperature trajectory proved to be acceptable in a conventional batch reactor with both heating and cooling systems. Experimental results revealed that the identified model is accurate; therefore, one can rely on the calculated optimal temperature trajectories to ensure that the polymer product quality conforms to the specification.