All‐optical poling behavior in side‐chain azobenzene homopolymer

All-optical poling of side-chain azobenzene homopolymers PCN2 and PCN6, i.e. poly (6-[4-(4-cyanophenylazo) phenoxy] x-methylene methacrylate) for x = 2 and 6, with different spacer lengths was experimentally investigated. Due to the low absorption of the samples at 532 nm, it was found that there is a nearly quadratic increase in second-harmonic generation (SHG) when the film thickness of the sample films increases from 4 μm to 100 μm. The time constant τA of the fitted photoinduced SHG decay process shows that PCN2 and PCN6 have higher temporal stability than the typical guest–host DR1-PMMA system, and different methylene conjugation lengths give slightly different time constants for disorientation. The possible reason from the molecule structure is discussed in detail. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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