The synthesis and second-order nonlinear optical properties of a series of mixed-substituent poly(organophosphazenes) that possess covalently attached donor-acceptor-substituted, conjugated moieties are reported. The mixed-substituent polymers have the general structure [NP(OCH2CF3),(OR)y]n, where OR = 0(CH2CH2O)kC6H4(CH=CH)mC6H4NO2, where k = 1–3 and m = 1-3,O(CH2CH2O)3C6H4CH=CHC6H4-CN, OCH2CH2N(CH3)C6H4NO2, and OCH2CH2N(CH2CH3)C6H4N=NC6H4NO2 and x + y = 100%. Model compound studies were carried out with the cyclic trimers N3P3(OC6H5)(OR) and N3P3(OCH2CF3)5(OR), where OR = O(CH2CH2O)3C6H4CH=CHC6H4NO2. Molecular structural characterization for the high polymers was achieved by 1H and 31P NMR, infrared, and UV-visible spectroscopy, gel permeation chromatography, and thermal analysis. The second-order nonlinear optical properties of polymer films were evaluated by second-harmonic generation. Alignment of the nonlinear optical groups was achieved by application of an electric field by a corona discharge. The second-order nonlinear coefficients, d(33, of the polymer films were in the range d33 = 4.1–34 pm/V and were determined by a Maker fringe analysis of the data. The second-harmonic generation behavior decayed following removal of the electric field. The variation in the d33 values was correlated to the molecular structure and the percent incorporation of the chromophores.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry