The fast transient fluorescence technique (FTRT) was used for studying the swelling and dissolution of a glassy polymer formed by free-radical polymerization of methyl methacrylate (MMA). Anthracene (An) was introduced during polymerization as a fluorescence probe to monitor swelling and dissolution. Swelling and dissolution processes of disc-shaped poly(methyl methacrylate) (PMMA) glasses in a chloroform-heptane mixture were monitored by measuring the fluorescence lifetimes of An from its decay traces. A method is developed for low quenching efficiencies for measuring lifetimes, tau, of An, and it was observed that tau values decreased as the dissolution process proceeded. Desorption, D, and mutual diffusion, D-m, coefficients of An molecules were measured during dissolution of PMMA and found to be around 5.4 x 10(-6) (cm(2)/s) and 2.2 x 10(-5) (cm(2)/s), respectively.