A Fast Transient Fluorescence Technique (FTRF) was employed for studying swelling of disc
shaped poly (methyl methacrylate) (PMMA) gels, which were prepared by free radical copolymerization of
methyl (methacrylate) (MMA) using various ethylene glycol dimethacrylate (EGDM) contents at 60 ∘C. Pyrene (P) was introduced as a fluorescence probe during polymerization. Swelling experiments were performed
by using P doped PMMA gels under chloroform vapor and in chloroform at room temperature. P lifetimes
in and out of the gel were measured from fluorescence decay traces during in-situ swelling experiments.
It was observed that P lifetimes in the gel decreased as swelling proceeds. An equation is derived for low
quenching efficiencies to interpret the behavior of P lifetimes during swelling. The Li-Tanaka equation was
used to determine the cooperative, Dc diffusion coefficients for the gels made at various crosslinker contents.
It is observed that Dc values decrease as the crosslinker content is increased both in chloroform vapor and
in chloroform.
