Strobe Master System (SMS), is introduced for studying THE swelling of disc shaped gels in chloroform-heptane mixtures. Gels were prepared by free radical copolymerization of methyl (methacrylate) (MMA) and ethylene glycol dimethacrylate (EGDM). Pyrene (P) was introduced as a fluorescence probe during polymerization and the existence of P were measured using (SMS) during in situ swelling processes. Various percents of chloroform in chloroform-heptane mixtures were used as a swelling agent. For the duration, tau(2) of P in the gel were found to be decreased as swelling proceeded. Li-Tanaka's equation was employed to determine the time constants, tau(c) and cooperative diffusion coefficients, D-c which were found to be decreased and increased respectively by increasing the chloroform content in the solvent mixtures.