| 초록 |
Nonlinear optical (NLO) materials based on organic compounds have been extensively studied over the past decade because of their potential applications in the field of telecommunications, optical signal processing, optical switching, etc. Among the organic materials NLO polymers are considered as a good candidate for making electro-optic (EO) devices, mainly because they offer many advantages such as light weight, chemical resistance, and good processability to form EO devices. In the developments of NLO polymers for EO device applications, stabilization of electrically induced dipole alignment is important considerations. Polyurethane matrix forms extensive hydrogen bond between urethane linkage and increases rigidity preventing the relaxation of induced dipoles. Physically crosslinked systems via hydrogen bonds have the advantages such as homogenity and good processibility relative to the chemically crosslinked systems. In this work we prepared novel polyurethanes containing dioxynitrostilbenyl unit as a NLO-chromophore. 2,3-Di-(2-hydroxyethoxy)-4-nitrostilbene (2) were prepared by the reaction of 2-iodoethanol with 2,3-dihydroxy-4-nitrostilbene (1). Diol 2 was condensed with 2,4-toluenediisocyanate to yield polyurethane 3 containing the NLO-chromophore 2,3-dioxy-4-nitrostilbenyl group. Polymer 3 was soluble in common organic solvents such as acetone and DMSO. Tg value obtained from DSC thermogram of the resulting polymer was 88 oC. Polymer 3 showed a thermal stability up to 300oC in TGA thermograms. |
