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A combination of several methods and quantitative parameters (fraction p of immobilized monomer units, apparent molecular weight, and size, number, and concentration of aggregates) as a function of time, temperature, and polymer concentration were used to obtain data characterizing aggregation of syndiotactic poly(methyl methacrylate) in n-butyl acetate. The thermal history of the sample (viz., the content of surviving nuclei which were identified with aggregates of globules formed during the intramolecular condensation) was shown to be decisive for the setting in and steepness of the aggregation process. Another "hysteretic" effect has been found by NMR for the equilibrium value of p at elevated temperatures. Regarding all experimental and reported data, a plausible qualitative model of aggregation was suggested; three processes, "globulation", nucleation, and flocculation, were recognized and characterized.

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