Temperature-dependent fluorescence of acrylic polymers containing benzyl groups

Fluorescence spectra were recorded as a function of temperature (10-60°C) for dilute dioxane solutions of four homopolymers containing the benzyl group in different positions with respect to the backbone, poly(α-benzylmethyl acrylate), poly(benzyl methacrylate), poly(monobenzyl itaconate) and poly(dibenzyl itaconate). In all cases the intensity decreases with increasing temperature. Arrhenius plots show two lines with different slopes intercepting at a point which we ascribe to a transition temperature between two states of the coil characterized by different activation energy parameters. The transition temperatures are around 29°C for all the systems except for poly(α-benzylmethyl acrylate) which gives simple linear behaviour without a transition. Activation energy parameters are compared for the different structures studied.