A. V. Lyubimov

Photochromic network polymers

New photochromic polymers having network structure have been studied. These polymers have been obtained on the base of spiropyrans (SP) with one or two polymerizable groups. It has been shown that the photochromic properties of SP molecules linked with macromolecules by one polymerizable group depend on supermolecular structure of network polymer. So, these SP molecules can be used as indicators of microheterogeneity of network polymer. It has been established that the photochromic behavior of SP molecules having two polymerizable groups is determined by the number of chemical bonds (one or two) of such a SP molecule with macromolecule. The copolymers of these SP molecules with alkyl methacrylates are of special interest because using these copolymers make it possible to create photochromic polymer material having large and adjustable time of storage of optical information.

Photochromic properties of indolinospironaphthooxazine in polymeric films

Conclusions1.The processes of the photocoloration and dark decoloration of indolinospironaphthooxazine in polymeric films are described on the assumption of the existence of two types of molecules of the initial and colored forms. The quantum yields of the photocoloration, the rate constants, and the energy of activation of the decoloration reaction are determined.2.A photophysical mechanism for the process of the photocoloration of indolinospironaphthooxazine, including the participation of the cis-cisoid isomer, is proposed.

Synthesis and photochromic properties of nitro-substituted spironaphthooxazines

Abstract7-Nitro- and 8-nitroderivatives of 1′,3′,3′-trimethylspiro[indoline-2′,3-3H-naphtho[2,1-b][1,4]oxazine] were synthesized, the last of them being prepared by direct nitration. The introduction of the nitro group stabilizes a bipolar colored form, the highest stability being exhibited when the NO2 group is the 8-position.

Photochromism of nitro-substituted spironaphthooxazines in polymer films

The photochromic properties of nitro-substituted spironaphthooxazines in polymer matrices of different polarity were investigated and the quantum yields of photocoloration and parameters of the dark decolorization reaction, which is a disperse process, were determined. The features of the behavior of the nitro-substituted spironaphthooxazines are determined by the more efficient reaction of the photoinduced form with the medium, which is the consequence of stabilization of the bipolar structure of the molecule of the colored form.

PMR spectra and structure of the open form of spironaphthooxazine

Conclusions1.The PMR spectra of the closed forms of spironaphthopyran and spironaphthooxazine were interpreted. The PMR spectra of the photoinduced forms of these compounds were obtained for the first time.2.The open form of spironaphthooxazine in nonpolar solvents was found to have the quinoid structure of one of the trans isomers, while there is a shift in the equilibrium toward the bipolar structure in polar solvents.

Inversion of configuration in the closed form of spirothiopyran molecules

ConclusionsThe ΔG≠value for the inversion of configuration of the closed form of spirothiopyrans is significantly greater than for their oxygen analogs due to steric hindrance for rotation of the rotation of the benzopyran fragment relative to the indoline fragment.

Synthesis and photochromic properties of spiroanthrooxazine

Abstract1′,3′,3′-Trimethylspiro[indoline-2′,3-3H-anthraceno[2,1-b][1,4]oxazine] was synthesized. The compound has photochromic properties in solutions and in polymeric matrices. It was found from the spectral data that the colored form of the spiroanthrooxazine exists in a quinoid form and is characterized by a positive solvatochromic effect.

Photochromic properties of 1,3,3-trimethyl-6′-nitrospiro (indolino-2,2′-[2H-1]benzothiopyran) in polymeric films

ConclusionsAn indolinobenzothiopyran with an electron-acceptor substituent- the NO2 group- in position 6 has been synthesized, and its photochromic behavior in various polymeric matrices has been investigated.

Photochromy of solutions of copolymers of spiropyran with two polymerization groups with alkyl methacrylates

Conclusions1.Copolymers of 1,3,3-trimethyl-5-methacryloylamino-6′-nitro-8′-methacryloylhydroxy-methylspiro(indoline-2,2′-[2H-1]-benzopyran) with different alkyl methacrylates and styrene were prepared. The copolymers have different solubility as a function of the nature of the comonomer.2.The photochromic properties of the prepared copolymers in solutions were studied. The complex nature of the kinetics of bleaching of the solutions of copolymers is due to the inclusion of the spyropyran molecules in the main chain of the polymer.