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<title>Photoinduced alignment of LC polymers by the combination of photo-orientation and thermotropic self-organization</title>

1999; SPIE; Volume: 3800; Linguagem: Inglês

10.1117/12.365801

1996-756X

Joachim Stumpe, Thomas Fischer, Michael Rutloh, Regina Rosenhauer, Johann G. Meier,

Liquid Crystal Research Advancements

The irradiation with linearly polarized light generates optical anisotropy in isotropic films of photochromic amorphous and liquid crystalline polymers due to photoorientation. The photochemically induced orientation of the photochromic side groups causes a co-operative orientation of the non-photochromic parts of the polymers such as the non-photochromic side groups. The orientational order photogenerated in the glassy state acts as an initializing force to align LC polymers by thermotropic self-organization on annealing above Tg. The combination of both ordering principles can result in a significant amplification of the light-induced in-plane anisotropy or, results alternatively in a homeotropic alignment of the side groups. The dependence of the photoorientation process and its thermal amplification on the liquid crystallinity, aggregation and the irradiation conditions is discussed.