The association behavior of a maleic anhydride grafted and pyrene labeled ethylene−propylene random copolymer was studied using fluorescence spectroscopy. The labeling was achieved with 1-pyrenebutanoic acid hydrazide via the grafted anhydride groups. The resulting polar grafts induced intra- and intermolecular associations among the polymer chains in apolar solvents. This association process was studied using steady-state and time-resolved fluorescence spectroscopy as a function of polymer concentration. Due to the high complexity of the polymer system, an improved approach of handling the time-resolved fluorescence data had to be introduced. Thus, the quantitative analysis of the fluorescence decays was carried out using a novel model in which the polymer network is divided into blobs among which the chromophores distribute themselves randomly, according to a Poisson distribution. Results show that, as the polymer concentration is increased, the number of polar group aggregates increases. However, the l...