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Light-sensitive thin films with n-phenylene chains in their structure are formed by deposition from a solution and by thermal vacuum deposition of bromine-modified polycyclohexadiene (Br-PCHD). It is found that the Br-PCHD films possess photoluminescence properties. Using IR-, UV-, and x-ray photoelectron spectroscopy methods, it is shown that during storage and exposure to UV irradiation in air the Br-PCHD films undergo structuring because of having been photooxidized by the molecular oxygen adsorbed on the surface.Introduction. Thin films of organic polymers with a developed conjugation chain (polyparaphenylene, polyphenylenevinylene, and their derivatives) are of great interest when developing electroluminescent materials and devices [1][2][3]. Since the production of thin films of polyparaphenylenes (PPPh) by traditional wet methods (pouring, centrifuging, pulverizing, etc.) is difficult because of their extremely low solubility, the methods of thermal vacuum deposition (TVD) of these polymers [4,5] are gaining in importance. In [6], practically defect-free, transparent TVD films of PPPh possessing photo-and electroluminescent properties were obtained.Earlier [7,8], it was shown that, on heating, bromide-modified polycyclohexadiene (Br-PCHD) is subjected to dehydrobromination, and, during thermal vacuum deposition onto a specimen, on its substrate a thin, highly sensitive film is formed, the structure of which contains n-phenylene chains. Using EPR-, IR-, UV-, and NMR spectroscopy, it has been established that the material of TVD films obtained from Br-PCHD is a co-oligomer of paraphenylene with cyclohexadiene (COPhC). The length of the chain of continuous conjugation (p) in the TVD film of COPhC, calculated according to [9], is equal to 2.6, which is close to the corresponding value for the TVD film of n-terphenyl (p = 2.4) selected as a model compound [8].The PPPh films and the films of the oligomers of n-phenylene (C 6 H 5 -(C 6 H 4 ) n -C 6 H 5 , where n = 1-4) deposited in vacuum emitted in the blue region of the spectrum [6]. It might be expected that the thin Br-PCHD films of COPhC would also possess luminescent properties.The aim of the present work is to study the photoluminescent properties of thin films of COPhC formed as a result of both deposition from a solution and thermal deposition in vacuum and also their conversion on exposure to UV irradiation.Experimental. Br-PCHD was produced as a result of interaction of PCHD with molecular bromine in a solution of chloroform similarly to [7]. The carefully purified product of bromination is a light yellow powder that is very poorly dissolved in chloroform, benzene, and carbon tetrachloride.The elemental composition of Br-PCHD is as follows: Predicted, %: C -30.03; H -3.37; Br -66.60 (C 6 H 8 Br 2 ). Found, %: C -35.10; H -4.01; Br -62.17 (C 6 H 8.1 Br 1.6 ).To obtain a soluble product, Br-PCHD was heated for 14 h at a temperature of 190-200 o C and a pressure of about 10 −2 torr. After the thermal treatment, the content of bromine in the specimen was e...

The features of photoisomerization and photoorientation of azo dye brilliant yellow (BY) in the thin film state are studied. The trans-cis-isomerization of the dye molecules is established to proceed upon irradiation of the films based on BY with a full light of an ultra-high pressure lamp DRT-1000 (UV / VID light), this reaction is described by the first-order reaction equation. Under the action of linearly polarized blue light (λ = 457 nm), an optical anisotropy arises in films of BY. Optically anisotropic films of BY with a high dichroic ratio (>10) are shown to be formed using N-methylpyrrolidone and N, N-dimethylformamide as solvents and cellulose acetate as the polymer matrix.

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