Polarized light-induced photoisomerization in glassy poly(methyl methacrylate) and local relaxation processes of the polymer matrix

Imamura, Yuji; Yamaguchi, Youichi; Tran-Cong, Qui

doi:10.1002/(sici)1099-0488(20000301)38:5<682::aid-polb5>3.0.co;2-j

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…In solid matrixes, the isomerization of spiropyranes , and the cis−trans isomerization of stilbenes , and azo compounds − are studied most often. The interest in the latter is due also to employment of azo dyes in the devices designed to store information.…”

Section: Introductionmentioning

confidence: 99%

Dynamical Heterogeneity in Glassy o-Terphenyl: Manifestation of Environment Changes in Photoisomerization Kinetics of Probe Molecules

Grebenkin

Большаков

2007

J. Phys. Chem. B

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A new method for the investigation of dynamical heterogeneity in glassy matrixes is presented and illustrated by the example of o-terphenyl (OTP). UV-vis absorption spectroscopy has been used to monitor the cis-trans isomerization kinetics of probe molecules in glassy OTP. The dependence of isomerization quantum yield on light intensity has been established. This dependence is shown to be due to the change in the local environment of the probe molecules. The simple model is suggested to estimate the time required for the environment to change, tauex. The tauex values from 2.6 x 10(2) to 1.9 x 10(5) s have been obtained for environments of molecules of 1-naphthylazomethoxybenzene (NAMB) in OTP over a temperature range from 244 to 204 K (Tg+1 to Tg-39 K). The temperature dependence of exchange time has a non-Arrhenius character. As the temperature decreases, an increase in exchange time slows down. The activation energy of the relaxation process is 54 kJ/mol over the range of 224-239 K.

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Section: Introductionmentioning

confidence: 99%

Dynamical Heterogeneity in Glassy o-Terphenyl: Manifestation of Environment Changes in Photoisomerization Kinetics of Probe Molecules

Grebenkin

Большаков

2007

J. Phys. Chem. B

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“…Therefore, the observed behaviour in Am/Stl should be caused by the larger required free volume for the stilbene photoisomerisation compared to azobenzene units. Results reported in the literature on the photoisomerisation kinetics of 4-methoxystilbene (4-MeOStl) into a PMMA matrix [35] induced by irradiation with linearly polarised light in the glassy state indicate that the photoisomerisation of 4-MeOStl requires a certain critical free volume (V f * ) for the internal rotations of the molecule around the C]C double bond. For the 4-MeOStl molecules located in the environments with the V f z V f * , it was found that the reaction proceeds slowly, whereas the photoisomerisation takes place much faster in the regions satisfying V f [ V f * .…”

Section: Photoinduction Of Anisotropymentioning

confidence: 99%

Photo-induced anisotropic films based on liquid crystalline copolymers containing stilbene units

Giménez¹,

Piñol²,

Serrano³

et al. 2006

Polymer

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“…The monomolecular reactions in amorphous matrices have been studied for a long time. The most frequently used reactions are the cis−trans isomerizations of azo-compounds − and stilbenes ,,, and isomerization of merocyanines. − There also are examples of more rare reactions, for example, racemization …”

Section: Introductionmentioning

confidence: 99%

Dynamical Heterogeneity in Glassy o-Terphenyl. 2. Measurement of Environment Structure Lifetime Using Reversible Reactions

Grebenkin

2008

J. Phys. Chem. B

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A new method is proposed for measuring the lifetime of heterogeneities in a glassy matrix. UV-vis absorption spectroscopy has been used to monitor the kinetics of photoinduced cis-->trans isomerization of 1-naphthyl-azomethoxybenzene (NAMB) in o-terphenyl (OTP) below T(g). The dependence of isomerization rate on the duration of dark interval after generation of cis molecules was established; an increase in the dark interval causes a decrease in isomerization rate. This dependence is shown to be due to the change in the local environment of NAMB molecules. The time required for the environment to change was estimated over a temperature range of 234 (T(g) - 9 K) to 241.5 K (T(g) - 1.5 K). The change in the environment of the guest molecules has been interpreted in terms of the exchange processes. The values obtained for the exchange time coincide with the rotation times of the NAMB molecule. Also, it is shown that the time of structural rearrangement of the environment near the fast reacting molecules is of the same order of magnitude as the time of structural rearrangement of the environment near the slow reacting ones.

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Polarized light-induced photoisomerization in glassy poly(methyl methacrylate) and local relaxation processes of the polymer matrix

Cited by 7 publications

References 17 publications

Dynamical Heterogeneity in Glassy o-Terphenyl: Manifestation of Environment Changes in Photoisomerization Kinetics of Probe Molecules

Dynamical Heterogeneity in Glassy o-Terphenyl: Manifestation of Environment Changes in Photoisomerization Kinetics of Probe Molecules

Photo-induced anisotropic films based on liquid crystalline copolymers containing stilbene units

Dynamical Heterogeneity in Glassy o-Terphenyl. 2. Measurement of Environment Structure Lifetime Using Reversible Reactions

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