Spectroscopic investigations of a novel push–pull azo compound embedded in rigid polymer

Wang, G.; Gan, Fuxi; Wang, Jian Wen; Yang, Lisong; Xu, Zhizhan

doi:10.1016/s0022-3697(01)00187-1

Cited by 6 publications

(4 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Figure 5, the absorption spectra show a “nearly” Gaussian distribution, indicating no other significant species (such as strong intermolecular interactions) exist. When compared with the polymer solution, the broader absorption band of the film is the result of the distribution of different aggregate states of the polymer molecules 21, 22. Similarly, absorbance measured for three cycles by either increasing or lowering the temperature almost overlap as shown in Figure 5.…”

Section: Resultsmentioning

confidence: 99%

Unique UV absorbance for triphenylimidazole‐based polymer

Liao

Nie

Chen

et al. 2012

J of Applied Polymer Sci

View full text Add to dashboard Cite

In this study, a novel vinyl polymer containing 2,4,5-triphenylimidazole side groups was synthesized through conventional radical polymerization, which possesses the characteristic of temperature-dependent absorbance in the near-ultraviolet (UV) spectral region. The linear dependence of UV absorbance on temperature was confirmed for the polymer both in solid state and in solution by experiment and also supported by the results of theoretical investigation.

show abstract

Section: Resultsmentioning

confidence: 99%

Unique UV absorbance for triphenylimidazole‐based polymer

Liao

Nie

Chen

et al. 2012

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…[25][26][27][28] Although a large variety of diarylazo compounds are used in the design of optical materials, only a few reports concerning the photoisomerization of heterocyclic azo dyes can be found in the literature. [29][30] In the last years we have synthesized a large variety of heterocyclic azo dyes substituted by electron-donating and electron-withdrawing groups ('push/pull' substitution pattern) that possess solvatochromic, photochromic and nonlinear optical (NLO) properties which are influenced by the electronic nature of the -conjugated bridge (thienylpyrrole or bithiophene) and by the substitution pattern on the aryl and heteroaryl-diazene moieties (Figure 1). [31][32][33][34][35][36][37][38] Figure 1 Earlier, we observed that bithiophene azo dyes exhibit photochromic properties at room temperature, although the speed of the photo and thermal isomerization is quite slow: visible light irradiation of phenyl substituted 2,2'-bithiophene azo dyes, in solution, leads in less than 30 s to a significant decrease of the absorbance at  max (35-50%) due to the conversion of the E-isomer to the Z-isomer.…”

Section: Methodsmentioning

confidence: 99%

Enhancement of the photochromic switching speed of bithiophene azo dyes

Coelho

Castro

Fernandes

et al. 2012

Tetrahedron Letters

View full text Add to dashboard Cite

A series of heteroaryl substituted bithiophene azo dyes in solution were irradiated with visible light to promote the azo E-Z isomerization and then the kinetics of the thermal Z-E back reaction was studied. The speed of this process is strongly influenced by the nature of the aromatic ring linked to the N=N function. While thiazole bithiophene azo dyes exhibit high switching speeds between the two isomers, but limited interconversion, for benzothiazole and substituted thiadiazole bithiophene azo dyes the switching between the two photoisomers can be performed in 3 seconds with a significant conversion of the trans-isomer to the thermal unstable cis-isomer (19-21%) and therefore a notable variation of the visible spectrum is observed.

show abstract

“…There are few reports where a variety of azo compounds are studied in the same conditions and none of them include heterocyclic azo dyes [1,[33][34][35][36][37]. These type of compounds have only recently been the subject of an extensive study [38][39][40][41][42][43]. Besides their classic applications as synthetic dyes and pigments, heteroaryl diazo chromophores containing five-membered aromatic heterocycles, exhibit second-order nonlinear optical (NLO) [44][45] as well as photochromic properties.…”

Section: Introductionmentioning

confidence: 99%

Fast thermal cis–trans isomerization of heterocyclic azo dyes in PMMA polymers

et al. 2013

View full text Add to dashboard Cite

A series of heterocyclic azo dyes were dispersed in poly(methyl methacrylate) (PMMA) matrix and the photochromic properties of the coloured films studied by UV-Vis spectroscopy. Visible irradiation of the coloured films lead to a fast decrease in the colour intensity due to the trans-cis photoisomerization reaction. When the light source was removed the spontaneous thermal cis-trans reverse isomerization occurred bringing the absorbance back to initial value with variable speed. Contrary to common azobenzenes that after photoisomerization with UV or visible light exhibit very slow thermal cis-trans back re-isomerization, that can last for hours or days, azo dyes bearing pyrrole, thiophene, thiazole or thiadiazole heterocycles display very fast switching between the two isomers (few seconds) even when dispersed in PMMA polymers.

show abstract

Spectroscopic investigations of a novel push–pull azo compound embedded in rigid polymer

Cited by 6 publications

References 22 publications

Unique UV absorbance for triphenylimidazole‐based polymer

Unique UV absorbance for triphenylimidazole‐based polymer

Enhancement of the photochromic switching speed of bithiophene azo dyes

Fast thermal cis–trans isomerization of heterocyclic azo dyes in PMMA polymers

Contact Info

Product

Resources

About