• Title/Summary/Keyword: absorption spectra

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Thermochromism of Spiropyran and Spirooxazine Derivatives (Spiropyran과 Spirooxazine 유도체의 열변색 현상)

  • Yoon Sang Lee;Jong Gyu Kim;Young Duk Huh;Myoung Kun Kim
    • Journal of the Korean Chemical Society
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    • v.38 no.12
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    • pp.864-872
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    • 1994

  • Absorption spectra of thermochromic spiropyran and spirooxazine derivatives were investigated. The effects of solvent polarity on the absorption spectra indicate that the merocyanine-like form of non-substituted spiro compound is likely to the quinoid type. However, the merocyanine-like form of electron-withdrawing substituted spiro compound is likely to the zwitter-ion type. The enthalpy changes between the closed and merocyanine-like forms were measured. The enthalpy change of spiro compound decreases as the solvent polarity increases. The UV-Vis spectrum of merocyanine-like form was resolved into three Lorentzian-Gaussian product bands. The solvent dependence of the amount of the three band was also examined.

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Kinetic Studies of the Aggregation of 3,3'-Diethyl Oxacarbocyanine onto Polyacrylic Acid (폴리아크릴산 용액에서의 옥사카르보시안닌 색소분자의 회합현상에 대한 반응속도론적 연구)

  • Lee, Hong;Im, Eun Suk;Bae, Hyeon Ok
    • Journal of the Korean Chemical Society
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    • v.38 no.11
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    • pp.792-799
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    • 1994

  • The spectral changes of 3,3'-diethyl oxacarbocyanine(DOC) in the aqueous solution and in the presence of polyacrylic acid(PAA) were studied by means of absorption and fluorescence spectroscopy. The spectral change of DOC in the aqueous solution with concentration changes is attributed to the formation of dimer. In the presence of PAA, the characteristic changes of metachromatic band with changes of P/D (the ratio between available binding site and the dye concentration) are found and the discussions are made in terms of stacking theory. A kinetic study of the interaction between DOC and PAA was also investigated by the absorption and fluorescence stopped-flow spectroscopy. The observed relaxation effect in PAA-DOC system can be described quantitatively by assuming two relaxation processes occur.

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