Second-Order Nonlinear Optical Active Calix[4]arene Polyimides Suitable for Frequency Doubling in the UV Region

A new type of soluble calix[4]arene-based polyimides was prepared by reaction of bis(3-aminopropyl) dipropyl functionalized tetranitrocalix[4]arenes with hexafluoroisopropylidene diphthalic anhydride. Spin-coating of these polymers and subsequent electric field poling results in films that are highly transparent above 410 nm and exhibit high and thermally stable second harmonic generation coefficients. These properties make these materials very suitable for frequency-doubling applications in the UV region (820−410 nm).