Photoproduct distribution in films of cinnamate polymers was analyzed to reveal the contribution of both photoisomerization and photodimerization to LC alignment photoregulation. A polymethacrylate with o-cinnamate side chains displayed preferential formation of Z-isomer while the dimerization takes place more favorably for other polymers including poly(vinyl cinnamate). On the basis of the relationship between photoproduct distribution and liquid crystal photoalignment and on the reversibility of the photoinduced reorientation of a liquid crystal, it was concluded that the photoalignment results from the polarization photoisomerization of cinnamate residues in the same manner as that of photochromic moieties like azobenzenes, whereas the (2 + 2) photodimerization plays a role in enhancing the thermal stability of the homogeneous photoalignment.

Polymethacrylates with laterally attached azobenzenes were prepared to cause molecular reorientation of this chromophore in their thin films by linearly polarized irradiation with an exposure energy of less than ca. 100 mJ/cm2. A homogeneous alignment was induced by assembling a nematic liquid crystal cell using a substrate plate covered with the photoirradiated films. The alignment direction of the cell was controlled by changing the electric vector of the actinic light.

A novel spiro trialicyclic dianhydride, rel[1S,5R,6R]‐3‐oxabicyclo[3.2.1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐2′,5′‐dione) (DAn) was synthesized from itaconic anhydride (1) and cyclopentadiene via a Diels‐Alder reaction, nitric acid oxidation, and the subsequent dehydration with acetic anhydride. The structure of DAn was determined by NMR spectra and single crystal X‐ray diffraction. A series of soluble polyimides (PIs) having a spiro alicyclic unit in the main chain were prepared by the reactions of DAn with several diamines through a general two‐step polymerization method. Polymerization temperature affected inherent viscosities of poly(amic acid)s. Chemically imidized PIs had the inherent viscosities in the range of 0.10–0.49 dL/g. Due to the unsymmetric spiro alicyclic structure, the PIs showed excellent solubility in many organic solvents. Glass transition temperatures of PIs ranged from 215 to 279°C and some of them showed no glass transition temperature. The 10% weight loss temperatures under nitrogen were in a range of 355–430°C. Films of PIs obtained by the thermal imidization were wholly transparent and colorless.

A novel concept of acid proliferation to improve the photosensitivity of chemically amplified photoresist materials is described by presenting the autocatalytic fragmentation of acetoacetates having a (sulfonyloxy)methyl residue to liberate the corresponding sulfonic acid. 2-Methyl-2-((methane- or p-toluenesulfonyloxy)methyl)acetoacetates were designed to be subjected to the acid-catalyzed fragmentation through the corresponding acetoacetic acids which are readily decarboxylated and undergo the subsequent β-elimination to give a sulfonic acid which can act as the autocatalyst to lead to the increment of acid concentration in geometric progression. Among the acetoacetates tested, tert-butyl 2-methyl-2-((p-toluenesulfonyloxy)methyl)acetoacetate was the most suitable reagent for the present purpose because of its reasonable thermal stability. A nonlinear generation of the sulfonic acid was confirmed in the acidolytic transformation of the acetoacetate in nonpolar solvents and in a film of poly[4-((tert-butoxycarbonyl)oxy)styrene] (PBOCSt), respectively. It was found that the addition of the acetoacetate to a film of PBOCSt doped with a photoacid generator enhances the photosensitivity characteristics.

In-plane alignment of nematic liquid crystals was regulated by polarized-light-irradiation of a cell assembled with a silica plate, the surface of which was modified by attaching 4-hexyl-4'-hexyloxyazobenzene at its o-position through surface silylation. The photoisomerizability of the chemisorbed azo-chromophore was affected by their surface density and the nature of photoinactive co-modifiers. The efficiency of the photoregulation of liquid crystal alignment was optimized by two-dimensional dilution of the chromophore with ethyltriethoxysilane (ETS) or 3-aminopropyltriethoxysilane (ATS). As a result, favourable procedure was to modify a silica surface with a crude azo-silylating reagent contaminated by ATS. The rate of the photoinduced reorientation of liquid crystals was followed by monitoring the alteration of the alignment direction of a dichroic dye dissolving in a mesophasic layer upon exposure to linearly polarized light. Exposure energy for the in-plane reorientation of a liquid crystal was about lOOmJcm of 445nm light at elevated temperatures close to TNI. The effect of positional isomerism on the photoregulation was determined with the use of 4-cyano-4-hexyloxyazobenzene as a commander molecule. It was confirmed that the photoalignment efficiency was markedly enhanced by attaching the chromophore at the ortho-or metaposition. The exposure energy for the reorientation of a liquid crystal was reduced by linking the p-cyanoazobenzene at the meta-position so that the reorientation was complete with an exposure energy of 20 mJ cm-'.