Useful Spectrokinetic Methods for the Investigation of Photochromic and Thermo-Photochromic Spiropyrans

Maafi, Mounir

doi:10.3390/molecules13092260

Cited by 35 publications

(35 citation statements)

References 93 publications

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“…The determination of the photochromic parameters, such as the number, nature, and kinetic and spectral properties of the transient species formed under irradiation is not a trivial task because the photoproducts are too labile to be isolated in many cases [28]. As an illustration, the kinetic behavior of the unimolecular systems is considered (e.g., spiropyrans, spiroxazines, dihydroindolizines, which are of major importance for applications to ophthalmic lenses) [29].…”

Section: Introductionmentioning

confidence: 99%

Alternative UV Sensors Based on Color-Changeable Pigments

Viková¹,

Vik²

2011

ACES

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Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some solutions of problems of measuring photochromic textile sample by standard commercial spectrophotometric systems [2]. Main problem with measurement of kinetic behavior of photochromic pigments by standard spectrophotometer is relatively long time period between individual measurements (5 s) and impossibility of measuring whole color change during exposure without interruption of illumination of sample during measurement. It means, standard commercial spectrophotometers enable off-line measurement of kinetic behavior during exposure period and quasi on-line measurement during reversion period. Based on this problem, it is only possible to obtain precise data during reversion-decay process and growth process (exposure) is affected by high variability of data. Following this knowledge, we developed original experimenttal system with short time scanning of color change of photochromic samples during growth and decay period of color change. In this study it is presented new view on the relationship between intensity of UV-A radiation and color change half-life t 1/2 . Via this relation, it is demonstrated the possibility of the flexible textile-based sensors construction in the area of the radiation intensity identification.

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Section: Introductionmentioning

confidence: 99%

Alternative UV Sensors Based on Color-Changeable Pigments

Viková¹,

Vik²

2011

ACES

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“…Kinetic of coloration was used to evaluate Sp-Mc and Mc-Mc phases of molecules with assumption that permanent existence of mono form; so, it would be rational to expect a first order kinetic of coloration. 29,30 The results showed a non-first order kinetics which supports double open form (Fig. 6).…”

Section: 924-28mentioning

confidence: 86%

Symmetric Bis-Azospiropyrans: Synthesis, Characterization and Colorimetric Study

Nourmohammadian¹,

Abdi²

2013

Bulletin of the Korean Chemical Society

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Synthesis and characterization of some novel symmetric bis-azospiropyrans are reported in this study. These bis-azospiropyrans are bifunctional chromophores with two spiropyrans linked by a bis-azo extended aromatic system that produce more color strength (large molar absorption coefficient in mero forms) due to appending two azospiropyran chromophores on one molecule. ) at the same conditions. Such high molar absorption coefficients confers high sensitivity to light and more color intensity of mero form, that leads to improvement of their light sensitivity and better discrimination of spiro (OFF) form from mero (ON) ones in molecular switches. The structures were deduced from their MS, FT-IR, and 1 H-NMR spectroscopic data and CHN analysis. All the synthesized photochemically bifunctional compounds revealed fluorescent emission in their colorless form which was faded out after exposing to UV light. Fluorescence quantum yield values of the mero forms were 0.25-0.81 and two high fluorescence quantum yield values (0.60 and 0.81) were found in these series.

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“…Nevertheless, in the second case, the irradiation of a much thinner film (i.e. the film after stretching) led to a stronger spiropyran to merocyanine photoconversion owing to a much stronger irradiation energy per unit of film thickness [21][22][23][24]. The later effect was thus responsible for an increase in the maximum absorbance.…”

Section: Influence Of Film Stretchingmentioning

confidence: 99%

Photochromic Behavior of Spiropyran in Polyurethane Thin Films

Bhran

Fonteix

Hoppe

et al. 2010

The International Conference on Chemical and Environmental Engi

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The aim of this work is to characterize the photochromic properties of a commercial grade of polyurethane (PU) that contains small quantities of spiropyran (SP) [1-hexyle-3,3-dimethyl-6'-nitrospiro (indoline-2',2'-benzopyran)]. PU photochromic films were illuminated with ultraviolet irradiation (365 nm) at room temperature and the absorbance spectra are recorded after scanning from 400 to 800 nm (visible zone). The effects of film thickness, irradiation time, and SP concentration on the polymer photochromic response have been studied. Furthermore, the photochromic behavior of polymer films under stretching and the kinetics of thermal decoloration of these films will be discussed.

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Useful Spectrokinetic Methods for the Investigation of Photochromic and Thermo-Photochromic Spiropyrans

Cited by 35 publications

References 93 publications

Alternative UV Sensors Based on Color-Changeable Pigments

Alternative UV Sensors Based on Color-Changeable Pigments

Symmetric Bis-Azospiropyrans: Synthesis, Characterization and Colorimetric Study

Photochromic Behavior of Spiropyran in Polyurethane Thin Films

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