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A series of symmetric derivatives of 4-(dicyanomethylene)-2-methyl-6-(p-(dimethylamino)styryl)-4H-pyran (DCM laser dye) has been synthesized, and the nonlinear optical properties and thermal decomposition temperatures of each of the chromophores has been measured. The symmetric chromophores all have larger hyperpolarizabilities than one would expect based on their absorption maxima. Estimations of their oscillator strengths based upon UV/vis spectra are all well above 1.0. It is proposed that these compounds possess two excited electronic states close to each other in energy, both contributing to the hyperpolarizability in an additive fashion. Electro-optical absorption spectroscopy data and semiempirical calculations on a model compound support this hypothesis. The implications of these results with regard to the tradeoff between nonlinearity and transparency are discussed. The large dipole moments and high decomposition temperatures of these chromophores make them attractive candidates for use in electro-optic polymers.

Using polyimide as host in a guest-host thin film we demonstrate the first poled-polymer electro-optic response stable at temperatures up to 150 °C (samples poled and cured at 250 °C). A coplanar-electrode poling geometry is used so that the molecular alignment of the guest dye between the electrodes is coincident with the free volume of the host. We hypothesize that ‘‘high’’ temperature poling during the imidization process, when the polyimide forms rings and densifies, accounts for the excellent poled response stability.

A series of conjugated donor−acceptor trienes in which the central double bond is incorporated into an unsaturated isophorone, verbenone, or chromone ring has been synthesized. In each case, the donor group consists of an amine and an aromatic or heterocyclic ring system, and the acceptor is the dicyanomethylidene group. The nonlinear optical properties of each of the compounds has been measured and correlated with its structure. The dipole moments and molecular hyperpolarizabilities of these compounds, like those of other conjugated polyenes, are large enough to be used as the active components of electrooptic polymers. Unlike other donor−acceptor polyenes, however, these compounds exhibit the thermal stability required for such applications.

The synthesis and characterization, including detailed 'H, 2H, 31P, and 13C NMR analysis of [ (l,l-dideuteri0-2,2-dimethyl-4-penten-l-yl-K3C~~~*~) (dmpe)PtnlBF4, 1-adz, and its 3,3-dideuterio isotopomer, 1 -7 4 (dmpe = 1,2-bis(dimethylphosphino)ethane), are described. Thermolysis of each 1-a-dz and 1-y-dz was carried out a t 125 "C in several solvents to yield a 1/1 mixture of 1-a-dz and 1-ydz. The rate of rearrangement is cleanly first order. Thermolysis of 1-a-d2 between 81 and 125 "C in methylene chloride led to determinations of activation parameters, E, = 31.8(0.6) kcal/moland AS* = -0.5(1.6) eu (100 "C). AnX-ray crystalstructuredetermination was carried out on the compound. It crystallizes in the monoclinic space group P21/n (No. 14), with a = 19.337(11) A, b = 6.948(4) A, c = 17.260(9) A, B = 122.34(6)", V = 1959.3 A3, and 2 = 4. The structure was solved with heavy atom techniques and refined to a final R factor of 4.18 % . In the solid state, the coordinated vinyl group is slipped slightly out the plane of the molecule and is canted a t a dihedral angle of 52" from the molecular plane. The chelate ring shows only very slight distortions from a presumed strain-free shape. 2D NOESY spectra suggest that the in-plane conformation of the pentenyl chelate is at least partly populated in solution. (dmpe)Pt(CH2-c-C4H,)Cl, 11, was prepared. Thermolysis of 11 a t 110 "C yielded intractable metal-containing materials along with methylenecyclobutane and methylcyclobutane together in ca. 60 7% yield as the only identifiable organic products. Treatment of 11 with silver ion a t low temperatures in acetone or methylene chloride yielded two products in a 1:7 (NMR) ratio, methylenecyclobutane and a material stable only below 0 "C that is assigned the structure [ (4-penten-l-y1-~3C~~~~~)(dmpe)PtII]BF4 on the basis of its NMR spectrum.

We report development of the first all-polyimide system (cladding/core/cladding) suitable for fabrication of electro-optic waveguide devices on silicon substrates. The cladding layers are spun from a low optical loss, commercially available polyimide that is suitable for multilayer stacks. The electro-optic material consists of this same polyimide as host to a commercially available guest chromophore and is based upon our prior work on thermoplastic polyimides [J. F. Valley, J. W. Wu, S. Ermer, M. Stiller, E. S. Binkley, J. T. Kenney, G. F. Lipscomb, and R. Lytel, Appl. Phys. Lett. 60, 160 (1992)]. We present the materials and process development methodology with the results for this polymer system and demonstrate it by fabrication of an all-polyimide Mach–Zehnder modulator operating at 830 nm.

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We demonstrate the first polyimide guest/host system which exhibits stable electro-optic response after parallel-plate poling. Such systems are based on a class of polyimides which, once cured, possess a clear glass transition in their dielectric relaxation spectra, characteristic of thermoplasticity. After doping with compatible nonlinear optical molecules the polyimide host system can first be thermally imidized (cured) and then poled with an electric field. High glass transition temperatures are achieved leading to excellent thermal stability of the poled electro-optic response.