SCLC polymers

Cinnamates occupy an important place in the history of photochemistry. Schmidt and his co-workers [18] used the solid state photochemistry of cinnamic acid and its derivatives to develop the idea of topochemical control of photochemistry in the crystalline state. Minsk [19] developed poly(vinyl cinnamate) as the first polymer for photoimaging. The cinnamate chromophore is still commonly incorporated in photopolymers of all types, including LC polymers, to enable them to be photochemically cross-linked [20], and a number of reports of the photochemistry of such MCLC and SCLC polymers are summarized below. 

SCLC Polymers. There has been a series of papers on the synthesis and photochemistry of SCLC polymers containing the 4-alkoxyphenyl-4 -alkoxy-cinnamate chromophore, the same chromophore as that of the MCLC polymer, 1. Ritter and co-workers [37] were the first to examine the photochemistry of any SCLC cinnamate polymer. The DSC data reported for polymer 10 indicated the... 

Noonan and Caccamo [39] reported a detailed study of the synthesis and photochemistry of SCLC polymers such as 12 (also with the 4-alkoxyphenyl-4 -... 

Kawatsuki et al. [52] also studied SCLC polymers such as 22 in which the... 

Spiropyrans have been incorporated as photochromic moieties into many polymers [4,67]. Krongauz and his co-workers [68-72] have extended this work to include several types of SCLC polymers. Small molecule LC materials containing a spiropyran moiety have not yet been reported, presumably because typical spiropyrans are not sufficiently elongated. The covalent attachment of spiropyrans to rodlike mesogenic groups does afford quasi liquid crystals compounds with unusual metastable mesophases [4]. However, these compounds do not show LC... 

A large number of SCLC polymers with azoaryl photochromic chromophores have been studied [74] mainly with a view to applications in optical recording [2]. 

Eich, Wendorff, and their co-workers [80-83] were the first to use SCLC polymers for photooptical information recording. For example, the polymer, 36,... 

More recently Ikeda and Tsutsumi [113] have used a SCLC polymer, 49, in which all of the mesogens are photoactive, azoaryl groups. They irradiated (355 nm, Nd-YAG) surface aligned monodomain films of 49 in both the N phase at... 

Han et al. [115] reported the use of novel SCLC polymers of type 52, with two azobenzene mesogens in a side chain attached to a single tertiary carbon of the... 

Angeloni, Chiellini, and their co-workers [116-118] reported the synthesis and characterization of both MCLC and SCLC polymers containing the 4,4 -bisalkoxyazobenzene chromophore. These interesting materials photoisomerized in solution but their photochemistry in an LC mesophase was not reported. 

The synthesis and some aspects of the photochemistry and photophysics of a 2,6-dialkoxy-substituted anthracene SCLC polymer, 61, have been reported by... 

Ikeda et al. [54] studied the excimer-like fluorescence of phenylenediacry-late chromophores in MCLC polyesters of type 23. These results are discussed in Section III.B of this chapter. A correlation was noted between the excimer fluorescence lifetime and the AS values for mesophase formation. The less-ordered, more mobile mesophases had shorter excimer lifetimes presumably because of more facile nonradiative decay. Kurihara, Ikeda, and Tazuke [129,130] also studied the emission properties of SCLC polymers of type 64, containing the... 

McCulloch and Bailey [189,195] reported P values for a series of SCLC polymers based on a polystyrene backbone (Table 21). They showed that both the azo and stilbene link units exhibit a greater solvatochromic shift than their imine counterpart, which manifests itself as a larger hyperpolarizabil-... 

Regarding device design, considerable flexibility is possible, as the FLC polymer film can be coated on a single substrate or filled between two supporting substrates as is conventionally done with displays. Even a flexible optical storage film might be conceivable. This has been realized on the basis of nematic or SCLC polymers with a single plastic substrate by Bowry et al. [146). and svith Sc FLC polymers and two plastic substrates by Yuasu et aL (US). 

Side-chain liquid crystalline polymers (SCLC polymer nematic, S, or amorphous)... 

Freidzon et alP is one of the most recent examples of such studies. The X-ray diffraction patterns obtained at diflerent temperatures for the SCLC polymer... 

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