Dichroism of Poly(Methyl Methacrylate) Thin Films Doped with Disperse Orange 11 Molecules

We investigate the absorption spectra of poly (methyl methacrylate) (PMMA) thin films doped with Disperse Orange 11 (DO11) dye molecules which change under illumination with visible light. Dichroism measurements of the kinetics of the transmission changes at 472 nm at room and low temperatures (-60° C ± 2 °C) have been investigated. Our data show that the photoisomerisation reaction and the light-induced polar orientation depend on the molecular structure of the polymer. Simultaneous UV-visible spectroscopy at low temperature confirms the existence of two forms of DO11 molecules (keto and enol forms), which are responsible for the interaction with irradiating laser light and forming an anisotropic structure inside the PMMA/DO11 thin film.