Effects of critical concentration fluctuations on the photocyclization of a bichromophoric molecule in the one-phase region of polystyrene/poly(vinyl methyl ether) blends

The photocyclisation of 9-(hydroxymethyl)-10-[(naphtylmethoxy)methyl]anthracene (HNMA) in the miscible region of the blends can be well represented by the sum of two exponential functions of time. The temperature dependence of the reaction rates obeys the Williams-Landel-Ferry relaxation mechabism, indicating that conformational transitions of HNMA are controlled by the segmental free volumes of polymer chains in the blends. The thermodynamics interactions of the blend should be taken into account for the interpretation of the reaction kinetics oh HNMA