Anthony J. East

Observation of the photorefractive effect in a dialkylaminonitrostilbene copolymer

We report observations of the photorefractive effect in a 1:1 side-chain copolymer of N-methacryloxyethyl-N-methylaminonitrostilbene with methyl methacrylate. Without the addition of a photoconducting component, gratings were written in this polymer at 633 nm in 8-μm-thick films at low powers and were detected by use of a four-wave mixing measurement. Diffraction efficiencies of the order of 10−5 −10−4 were measured by four-wave mixing.

Thermotropic Poly(Ester-Amides) Based on Naphthalene Monomers

Abstract The structure and properties of a range of thermotropic poly(ester-amides) derived from 2,6-naphthalene derivatives is described. Many of these polymers may be melt-processed into fibers, monofils, and molded structures having very attractive physical and mechanical properties. A variety of monomers has been used and structure/composition/property relationships are described along with details of synthesis and processing conditions. Both fibers and molded articles may be heat-treated to enhance their tensile properties. Molded articles and extruded rods have exceptional tensile moduli in the unfilled state.

Photorefractive effect in an aminonitrostilbene side-chain copolymer

The photorefractive effect has been observed in a 1/1 side chain copolymer of N- methacryloxyethyl-N-methylaminonitrostilbene and methylmethacrylate. Holographic gratings were written in this polymer at 633 nm in 4 - 8 micrometers thick films at low laser powers and detected using four wave mixing and two beam coupling. The polymer which has a high linear electro-optic coefficient was intrinsically photorefractive and did not require the addition of photoconducting or charge generative components. Diffraction efficiencies on the order of 10-5 - 10-4 were measured by four wave mixing. Two beam coupling provided conclusive evidence that the observed effect was photorefractive in nature.

Electro-optic and nonlinear optical polymers and devices

Early work at Hoechst Celanese1 demonstrated that methacrylate polymers with mesogenic side chains could be made with reasonably large electro-optic activity. The mesogenic side chains are polar so that a non-centrosymmetric structure can be obtained by heating a film near its Tg in a strong d.c. electric field and thus orienting the side chains. In Figure 1, the general structure of methacrylate based electro-optic polymers using polar nitro-stilbene chromophores is shown.