Kazuo Tai

SYNTHESIS OF AZO CHROMOPHORES CONTAINING A PERFLUOROCYCLO-ALKENYL MOIETY AND THEIR SECOND-ORDER OPTICAL NONLINEARITY

Abstract 1,2-Bis[4-[4-[ N -ethyl- N -(2-hydroxyethyl)amino]phenylazo]phenylthio]perfluorocyclopentene, having two independent intramolecular push-pull chromophores in a molecule, showed the highest second-order nonlinear coefficient ( d 33 ) among the cyclobutenyl, -pentenyl, -hexenyl, and cyclopentenyl nitro derivatives in both doped poly(methyl methacrylate) (PMMA) and polycarbonate (PC).

Second-order optical nonlinearity of 6-(perfluoroalkyl)benzothiazolylazo dyes

Abstract The perfluorobutyl derivative showed a large second-order nonlinear optical coefficient ( d 33 ) and improved relaxation behavior in a series of 6-substituted benzothiazolylazo nonlinear optical chromophores (NLOphores).

Second-order optical nonlinearity of thiazolylazo chromophores containing hydroxyl groups

Bathochromic thiazolylazo second-order nonlinear optical chromophores (NLOphores) having 2-hydroxyethyl group(s) in a molecule have been prepared. The tris(2-hydroxyethyl) derivatives showed the best relaxation behaviour among the non-, mono-, bis- and tris(2-hydroxyethyl) ones doped in poly(methyl methacrylate-co-methacrylic acid).

Computer simulation of the fracture of perfectly oriented polymer fibres

Abstract Fracture of perfectly oriented polymer fibres was studied by means of a computer simulation technique based on the ultimate structure model in order to estimate the upper limit of the tenacity of polymers with finite molecular weight. The fracture mechanism was also investigated in terms of average molecular weight and different nature of interchain interaction. It was observed that the tenacity of the model fibres increased with molecular weight and tended to approach the theoretical limit for the infinite molecular weight. In the cases of lower molecular weight, significant broadening of the stress distribution was observed under elevated stress, and the fracture behaviour was plastic. In the cases of higher molecular weight, the stress distribution was quite narrow until significant number of bond-cleavages occurred, and the fracture was brittle. The primary factor of fracture was found to be the chain-slippage in the lower molecular weight cases, and chain-scission in the higher molecular weight cases. Higher tenacity was marked when the polar interactions were introduced, especially in lower molecular weight cases. This can be attributed to the enhancement of chain binding by the polar interactions and suppression of chain-slippage.

Second-Order Optical Nonlinearities in Perfluoroalkylsulfonyl Substituted Azo Dyes

Abstract The second-order nonlinear optical coefficients d33 (-2ω:ω, ω) of polymer films doped with novel azo dyes, which have a perfluoroalkylsulfonyl group as an electron acceptor and an extended π-electron conjugated system, are determined by second-harmonic generation (SHG) measurements. Thin polycarbonate (PC) film doped with 4-(4-(4-perfluorobutylsulfonylphenylazo) naphthylazo)-N-ethyl-N-hydroxyethylaniline showed a large d33 value, 67 pm/V, at a wavelength of 1064 nm. The decay of the d33 values was slow due to the stability of the molecular arrangement in a polymer matrix at high temperature. In addition, a side-chain nonlinear optical polymer with this novel disazo dye is synthesized and the decay of d33 values is estimated.

Second-order optical nonlinearities of novel disazo dyes having a perfluoroalkylsulfonyl group

The second-order nonlinear optical coefficients d33 (-2(omega) :(omega) ,(omega) ) of polymer films doped with novel disazo dyes, that have a perfluoroalkylsulfonyl group as an electron acceptor and an extended (pi) - electron system, are determined by second-harmonic generation (SHG) measurements at wavelengths of 900 - 1550 nm. Thin polycarbonate (PC) film doped with 4-(4-(4- perfluorobutylsulfonylphenylazo) naphthylazo)-N-ethyl-N-hydroxyethylaniline showed a large d33 value, 67 pm/V, at a wavelength of 1064 nm. The decay of the d33 value was slow due to the stability of the molecular arrangement in a polymer matrix at high temperature. The large d33 values and the stability of polymer films doped with novel disazo dyes in this study are discussed in terms of electron acceptor substitution and an extended (pi) -electron system.