A solution processible thiophene polymer with a hydrogen-bondforming urethane group in the side chain, viz., poly[2-(3-thienyl)ethanol n-butoxycarbonylmethylurethane] (PURET), has been synthesized. The polymer is soluble in a wide variety of solvents such as chloroform, dimethylsulfoxide, N-methylpyrrolidone, and trifluoroacetic acid among others. Optical quality thick films are obtained by solution casting. The presence of extensive hydrogen bonding is established with the help of temperature-dependent infrared spectroscopy. NMR spectroscopic sthdy indicates the presence of about 33% regio-isomeric defects in the polymer. The polymer forms yellow-colored solutions ( A, , , = 430 nm) in most of the organic solvents, while in trifluoroacetic acid the polymer is oxidized and exhibits an additional band with an absorption maximum at around 780 nm. The conductivity of the polymer is in the order of 1 S/cm.
Recently we have reported, significant second harmonic generation from spin coated and bulk films of a soluble polydiacetylene (PDA), namely poly{8-[[[butoxy carbonyl] methyl]urethanyl]-1-(5-pyrimidyl)-octa-l,3,-diyne}} (BPOD) without recourse to poling. Poly(BPOD) is an asymmetrically substituted PDA in which a polarizable heteroaromatic pyrimidyl group is attached as one of the side groups. In addition to reviewing the earlier results, we report a series of new soluble PDAs of the same class with further functionalization, elaborating on the already defined design principle.A second class of polymers with azo dye based NLO chromophores incorporated into the structure has been processed optically to fabricate holographic elements. Trans-cis-trans isomerization driven reorientation and macromolecular motion leads to the formation of surface relief gratings upon exposure to an interference pattern. Fabrication of optical elements based on these polymers will be elaborated.
Reproduction in whole or in part is permitted for any purpose of the United States Government. This document has been approved for public release and sale; its distribution is unlimited. ABT I RAG T (MaxImum ZOO WOW~s)Second harmonic generation from the spin coated films of an asymmetrically substituted polydiacetylene, namely poly((8-butoxy cardonyl)methyl urethanyl) 1-(5-pyrimidyl)-octa-1,3-diyne(BPOD) is reported for the first time. The macromolecules assemble to produce the organization responsible for SHG without recourse to poling. d33 of the spin coated film (0.19-0.31 mm thickness) are between 0.78-0.88 pm/V without absorption correction and 3.32-5.57 pm/V after correction. Angular and polarization dependence study of the second harmonic response suggests that the film has in-plane isotropy as a whole and the net dipole is nearly perpendicular to the film surface. Spontaneous orientation of the polymer chains during the film formation seems to be responsible for the noncentrosymmetric alignment of the polymer. SHG from the Langmuir Blodgett films are also reported. ABSTRACT Second harmonic generation from the spin coated films of an asymmetrically substituted polydiacetylene, namely poly((8-butoxy carbonyl)methyl urethanyl) 1-(5-pyrimidyl)-octa-l,3-diyne(B POD) is reported for the first time. The macromolecules assemble to produce the organization responsible for SHG without recourse to poling. d 33 of the spin coated film (0.19-0.31 gmn thickness) are between 0.78-0.88 pm/V without absorption correction and 3.32-5.57 pm/V after correction. Angular and polarization dependence study of the second harmonic response suggests that the film has in-plane isotropy as a whole and the net dipole is nearly perpendicular to the film surface. Spontaneous orientation of the polymer chains during the film formation seems to be responsible for the noncentrosymmetric alignment of the polymer. SHG from the Langmuir Blodgett films are also reported.
The objective of this investigation was to develop stable nonlinear optical (NLO) materids which possess both second and third order NLO properties. These materials were envisioned as having a polydiacetylene (PDA) backbone with a second order active NLO chromophoric substituent. The choice of a PDA backbone in this investigation was twofold. In terms of third order NLO properties, the extensive n-conjugation of the PDA backbone leads to large ultrafast third order effects. In terms of second order NLO properties, the high thermal stability and rigidity of the PDA matrix in a perfect polymeric single crystal is expected to prevent the randomization of the NLO chromophores in the noncentrosymmetric environment. This paper focuses on the synthesis, FT-Raman structural analysis, and NLO properties of the unsymmetrical diacetylene monomers, ((9-Butoxy carbonyl) methyl urethany1)-1 -(4-urethanyl-4'-nitrobiphenyl)-nona-2,4-diyne, and ((9-Butoxy carbonyl) methyl urethany1)-1-(4-urethanyl-4'-nitroazobenzene)-nona-2,4-diyne.
The objective of this investigation was to develop stable nonlinear optical (NLO) Materials which possess both second and third order NLO properties. These Materials were envisioned as having a polydiacetylene (PDA) backbone with a second order active NLO chromophoric substituent consisting of a donor group, a π-conjugated bridge, and an acceptor group. The choice of a PDA backbone in this investigation was twofold. In terms of third order NLO properties, the extensive π-conjugation of the PDA backbone leads to large ultrafast third order effects. In terms of second order NLO properties, the high thermal stability and rigidity of the PDA Matrix in a perfect polymeric single crystal is expected to prevent the randomization of the NLO chromophores in the noncentrosymmetric environment. This paper focuses on the synthesis and NLO properties of the unsymmetrical diacetylene Monomers, ((9-Butoxy carbonyl) Methyl urethanyl) -l- (4-urethanyl-4'-nitrobiphenyl) -nona-2,4-diyne, and ((9-Butoxy carbonyl) Methyl urethanyl) -l- (4-urethanyl-4'-nitroazobenzene) -nona-2,4-diyne. The high entropy flexible urethanyl side group was chosen to satisfy the monomer packing requirements for polymerization and enhance the solubility of the PDAs.
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