The three-step polymerization of a well-defined polymeric silane coupling agent, triethoxysilyl-terminated polystyrene, catalyzed by acid (H3PO4), was traced as a function of the reaction time with gel permeation chromatography (GPC). Time-resolved GPC traces collected during the polymerization process were then used to construct two-dimensional (2D) correlation maps via generalized 2D correlation analysis. The results demonstrated that the synchronous and asynchronous 2D correlation GPC spectra directly reflected the dynamic variation of aggregate-aggregate interactions during each step of the polymerization. In particular, it was found that the formation of aggregates among the cyclic trimers (or tetramers) and monomers was critical for the preferential production of pentamers in the reaction system. (C) 2004 Wiley Periodicals, Inc.