We followed the polymerization reaction of living poly-alpha-methylstyrene in a solution of tetrahydrofuran as a function of temperature, near its ceiling temperature, using dynamic light scattering. We obtained three different relaxation times revealing three kinds of macromolecular species in the solution. One of the relaxation times corresponded to the formation of living polymer chains. In this particular case, we found that the average relaxation time increased as temperature was lowered due to polymer growth. Nevertheless, it did not follow the same track along a cooling-heating cycle. These results are consistent with an incomplete depolymerization reaction. For the other two species, we propose that they were the result of ionic aggregation.