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Poly(methyl methacrylate) doped with fluorescent perylene dye was prepared by both radical polymerization of methyl methacrylate and solvent casting from polymer solutions. The samples were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, electrical conductivity, and dielectric properties. Both conductivity and dielectric properties were measured in the temperature range 303-433 K and the frequency range 10 3 to 5 ϫ 10 6 Hz. The results show that the directcurrent electrical conductivity increased by increasing dye content in solvent-cast samples, whereas it decreased radically polymerized samples. The results of alternating-current conductivity suggest electron hopping between filled and empty localized states. The study of dielectric properties showed two relaxation peaks corresponding to the dipole segmental and dipole group losses. Explanations based on the polymer free volume and acid-base interactions were proposed to examine the influence of the sample preparation and perylene dye concentration on the glass-transition temperature and dielectric relaxation of the samples. The obtained results recommend the thermal and molecular stability of luminescent solar concentrator (LSC) matrices prepared by radical polymerization over those prepared by solvent casting.

The optical absorption of poly(methyl methacrylate) (PMMA), doped with perylene dye, prepared by both thermal polymerization and casting methods, has been measured before and after exposure to filtered or unfiltered light using xenon arc lamp or day light. The optical band gap of thermally polymerized PMMA was reduced by doping with perylene dye or exposure to UV radiation. Study of DSC and FTIR measurements confirmed that the samples prepared by thermal polymerization are more stable than solvent‐cast samples.© 2002 Society of Chemical Industry

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