Photocyclomerization of bis(9-anthrylmethyl) ether in solid polymers

Abstract

Photocyclomerization of bis(9-anthrylmethyl) ether (BAME) in solid polymers, polystyrene (PS) and poly(vinyl acetate) (PVAc), was observed over a wide range of temperatures. The rates of photocyclomerization in PS and PVAc matrices above T g followed a temperature dependence of WLF (Williams-Landel-Ferry) type, namely the intramolecular conformational transitions of BAME are governed by the free volume of polymer segments. Below T g in the PS matrix, the reaction rate is also affected by a secondary relaxation process of the polymer matrix ( T β ⋍ 60° C ), and at room temperature the yields of photocyclomerization are determined by the initial distribution of BAME frozen conformations in the PS matrix. Finally, the changes in refractive index involved in this reaction in solid PVAc were measured and the normalized refractive-index difference n o = 0.4 × 10 −22 cm 3 (D line) was obtained for BAME-doped (39 mmol l −1) PVAc film.