Cross-Linkable Zwitterionic Polyimides with High Electrooptic Coefficients at Telecommunication Wavelengths
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- 作者：Naiheng Song ; Liqiu Men ; Jian Ping Gao ; Yaowen Bai ; Andrew M. R. Beaudin ; Guomin Yu ; and Zhi Yuan Wang
- 刊名：Chemistry of Materials
- 出版年：2004
- 出版时间：September 21, 2004
- 年：2004
- 卷：16
- 期：19
- 页码：3708 - 3713
- 全文大小：102K
- 年卷期：v.16,no.19(September 21, 2004)
- ISSN：1520-5002
文摘
A series of nonlinear optical (NLO) polyimides were prepared by grafting 4-16 wt %zwitterionic pyridinium tricyanoquinonedimethane chromophore with a large negativehyperpolarizability (
0 = -590 × 10-30 esu) onto the host polyimides through an ester bondformation. To enhance the temporal stability of the poled NLO polymers, a new thermallyreactive group, i.e., 5-aminobenzocylcobutenone, was introduced into the NLO polymersystems to effect the cross-linking during the thermal poling process. The resulting NLOpolyimides showed good solubility in polar aprotic solvents such as N,N-dimethylformamideand could form uniform films by casting or spin coating without any noticeable chromophoreaggregation or phase separation as examined under an optical microscope. These NLOpolyimides had glass transition temperatures in the range of 170-213 
C and were thermallystable up to 270 C. The electrical resistivity of NLO polyimides was found to be on theorder of 1015 
·cm at 80 C and dependent on the applied voltages. As the temperatureincreased, the resistivity dropped monotonically to 2.4 × 1011 ·cm at 200 C. With a 10 wt% chromophore loading (or a number density of 15 × 1019 cm-3) in the polymer, theelectrooptic (EO) coefficient (r33 at 1550 nm) reached 45 pm/V. No substantial decrease inEO coefficients was observed after the test cell was kept in the dark at 85 C under nitrogenafter 1200 h nor when the test cell was irradiated with 1550 nm light (50 
W/~4 mm2) for10 h at ambient temperature in air.
0 = -590 × 10-30 esu) onto the host polyimides through an ester bondformation. To enhance the temporal stability of the poled NLO polymers, a new thermallyreactive group, i.e., 5-aminobenzocylcobutenone, was introduced into the NLO polymersystems to effect the cross-linking during the thermal poling process. The resulting NLOpolyimides showed good solubility in polar aprotic solvents such as N,N-dimethylformamideand could form uniform films by casting or spin coating without any noticeable chromophoreaggregation or phase separation as examined under an optical microscope. These NLOpolyimides had glass transition temperatures in the range of 170-213 C and were thermallystable up to 270 C. The electrical resistivity of NLO polyimides was found to be on theorder of 1015 ·cm at 80 C and dependent on the applied voltages. As the temperatureincreased, the resistivity dropped monotonically to 2.4 × 1011 ·cm at 200 C. With a 10 wt% chromophore loading (or a number density of 15 × 1019 cm-3) in the polymer, theelectrooptic (EO) coefficient (r33 at 1550 nm) reached 45 pm/V. No substantial decrease inEO coefficients was observed after the test cell was kept in the dark at 85 C under nitrogenafter 1200 h nor when the test cell was irradiated with 1550 nm light (50 W/~4 mm2) for10 h at ambient temperature in air.