Triple fluorescence of poly(methacrylates) with benzanilide side groups

The fluorescence behaviour of poly(methacrylates) with benzanilide side gro ups and that of related monomer model compounds are compared in solution, c rystalline state and as spin-coated films. The fluorescence of benzanilide is characterized by three competitive radiative processes. In addition to t he normal fluorescence Fl at 345 nm, a superposition of proton transfer (PT ) fluorescence and intramolecular charge transfer (ICT) fluorescence is obs erved, characterized by a large Stokes shift. The emission of the crystalli ne monomers, solid polymers and spin-coated films is caused by intermolecul ar interactions between the benzanilide moieties in form of hydrogen bonds and by an intramolecular charge transfer process. Because of the high effic iency of these interactions, the fluorescence intensity of the normal fluor escence is strongly decreased in solid states and glassy films. The deactiv ation behaviour of the polymers is investigated in dependence on the matrix properties varied by the temperature. Moreover, it is demonstrated that th e intermolecular interactions of the benzanilides are strongly influenced b y changes in its intramolecular properties like the modification of the par a-substitution of the benzanilide moieties. Photochemical deactivation proc esses affect neither the photophysical behaviour of the benzanilides in sol ution nor in the solid state. (C) 2000 Elsevier Science B.V. All rights res erved.