Electro-optic polymeric films of phenylethynyl dyes with transparency in the blue region of the visible spectrum

Easily processed electro-optic films are reported with potential for >100 GHz switching speeds. Dyes of the general chemical structure 1-(4-[N-ethyl-N-(2-hydroxyethyl)-amino]-phenylethynyl)-4-(4-cyanophenylethynyl)-2,5-disubstituted benzene were attached as side groups to a polyimide backbone. Substituents on the central ring of the three-ring dye prevented aggregation at high concentrations of dye. These amorphous films exhibited absorption maxima in the range of 375–395 nm. A film containing 25% dye attached to polyimide was poled to give an electro-optic coefficient (r33) of 12 ± 2 pm/V at 532 nm. Its properties were compared with the measured linear and nonlinear optical properties of several previously published dyes that have transparency in the blue-green part of the visible spectrum.