The transport of different dye solute molecules from various dye-donor polymer films to a constant dye-acceptor polymer film has been investigated. At constant dye concentration, the transport of all dye molecules from the dye-donor was found to be controlled by the Tg of the dye-polymer mixture. The data was found to fit well with free volume considerations. Further investigations were accomplished to understand the parameters influencing the key factor of dye-polymer blend Tg. This was found to depedn on the polymer Tg, the dye solute Tg, their relative concentrations and dye-polymer affinity. Attempts were made to correlate increases in Tg with dye-polymer affinity using solubility parameters as a predictive tool and exellent correlation's were established. The Tg was low when there was a large mismatch in solubility parameters, increased as dye and polymer became more compatible and reached a miximum when the solubility parameters of both components were equal. The results demonstrate the need for complementary dye and polymer materials design.
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