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Phosphorescence Decay and Dynamics in Polymer Solids

“…The Seviation was attributed to the diffusion-controlled^hydrogen^abstraction reaction between benzophenone triplet and the PVA matrix (33). The occurrence of non-exponential decays in poly(vinyl alcohol) where there is no possibility of triplet energy migration is an additional proof of the absence of the T-T annihilation mechanism in the phosphorescence decay of benzophenone in polymer matrices.…”

“…The occurrence of quenching was ascertained by comparison with the model quenching rate constant of benzophenone triplet by methyl acetate in acetonitrile solution (3.9x10 M" S" at 30°C) (28). Quenching of benzophenone triplet by phenyl or phenylene groujs jn polystyrene or polycarbonate has also been studied (1.2x10 M s~ for polystyrene in benzene at 30°C) (30).…”

Photodegradation of O‐methacryloyl ketone oxime‐methyl mechacrylate copolymers in the solid phase

“…It has been found that the rate of photolyses of A01 groups does not depend on whether oxygen is present or notg and it is reported that the presence of oxygen induces the formation of ketone by the reaction of imino radicals with oxygenlo as shown in Eq. (8). With copolymers containing MABPO as one component, it is expected that the amount of BP liberated by photolysis increases with increase in the concentration of the decomposed A01 groups and that the accelerated degradation of polymers by the increased amount of BP occurs.…”

Luminescence Studies of Polymer Matrices: 4. Phosphorescence of Benzophenone Dispersed in Acrylic Acid Based Polymer Films

“…Energy transfer from the dispersed triplet state to the polymeric host has also been recognized [4,12,[17][18][19][20][21][22][23] as a significant determinant of the overall thermal dependence of phosphorescence in the bulk state. Studies of the photophysical behaviour of benzophenone (BP) have featured strongly in such investigations [12,[17][18][19][20][21][22][23]. The fact that the decay of phosphorescence of BP dispersed in PMMA does not follow a simple exponential decay law at temperatures between the onset of the β relaxation and the glass transition (T g ) has been reported by several research groups [12,[17][18][19][20][21][22][23].…”

“…Studies of the photophysical behaviour of benzophenone (BP) have featured strongly in such investigations [12,[17][18][19][20][21][22][23]. The fact that the decay of phosphorescence of BP dispersed in PMMA does not follow a simple exponential decay law at temperatures between the onset of the β relaxation and the glass transition (T g ) has been reported by several research groups [12,[17][18][19][20][21][22][23]. Two main mechanisms have been proposed to explain such behaviour.…”