ABSTRACT
We report the observation of a self-written waveguide inside a bulk methylene blue sensitized poly/vinyl alcohol)/acrylamide photopolymer material. Light from a low power He-Ne laser is focused into the material, and the evolution of the beam is monitored. The refractive index of the material is modulated in the region of high intensity due to photobleaching and photopolymerization effects occurring in the material. As a result, the beam propagates through the medium without any diffraction effects.
ABSTRACT
The ground state and excited state dipole moment of a series of alkyl substituted para-nitroaniline derivatives is reported. Ground state dipole moment was determined by the Debye-Guggenheim method and the excited state dipole moment was estimated using the solvatochromic method. For all molecules under investigation, the excited state dipole moment was found to be higher than the ground state dipole moment. The molecules exhibited positive solvatochromism.
Subject(s)
Aniline Compounds/analysis , Aniline Compounds/chemistry , Acetonitriles/chemistry , Chemistry Techniques, Analytical/methods , Coloring Agents/pharmacology , Light , Models, Chemical , Models, Molecular , Models, Statistical , Molecular Structure , Solvents/chemistry , Spectrometry, Fluorescence/methodsABSTRACT
The nonlinear optical molecule N,N-bis(4-bromobutyl)-4-nitrobenzenamine was synthesized. The ground state dipole moment was determined by the Debye-Guggenheim method. A solvent mixture of acetonitrile and toluene was used for the solvatochromic determination of the excited state dipole moment. Excited state has a high value for the dipole moment which indicated a higher degree of charge transfer from the donor to the acceptor moiety on excitation by light. The first hyperpolarizability (beta(ijk)) of the molecule was evaluated assuming the two level model of the first hyperpolarizability.
