Stable second‐order nonlinear optical poly(amide–imide)/inorganic materials via simultaneous sequential self‐repetitive reaction and sol–gel process |
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Authors: | Hsun‐Lien Lin Tsung‐Yi Chao Yeng‐Fong Shih Shenghong A Dai Wen‐Chiung Su Ru‐Jong Jeng |
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Institution: | 1. Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan;2. Department of Applied Chemistry, Chaoyang University of Technology, Taichung County 41319, Taiwan;3. Chung‐Shan Institute of Science and Technology, Lungtan, Tauyuan 325, Taiwan |
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Abstract: | A series of thermally stable organic/inorganic second‐order nonlinear optical (NLO) composites via sequential self‐repetitive reaction (SSRR) and sol–gel process has been developed. This SSRR is based on carbodiimide (CDI) chemistry. The difunctional azo chromophores (2,4‐diamino‐4′‐(4‐ nitrophenyl‐diazenyl)azobenzene (DNDA)) was reacted with excessive amount of 4, 4′‐methylene‐ diphenylisocyanate (MDI) to form poly‐CDI, and subsequently trimellitic anhydride (TMA) was added to obtain poly(N‐acylurea). The organic/inorganic composites containing prepolymer of phenyltriethoxysilane (PTEOS) and poly(N‐acylurea) in different weight ratios (10:90, 30:70, 50:50, 70:30, 90:10 wt%) were prepared, respectively. The moderate glass transition temperature (Tg) characteristic of the poly(N‐acylurea) allows the NLO‐active polymer to achieve high poling efficiency. After in situ poling and curing process, the Tgs of the composites were elevated, and higher than that of the pristine poly(amide–imide) sample. Electro‐optical (EO) coefficients (r33) of about 5.5 ~ 18.0 pm/V at 830 nm were obtained. Excellent temporal stability at 100°C, and waveguide characteristics (3.1–4.2 dB/cm at 830 nm) were also obtained for these composites. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | semi‐IPN poly(amide– imide) NLO sequential self‐repetitive reaction sol– gel process |
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