• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1714-1716
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• 2000

We fabricated the optical system of merocyanine dye using Langmuir-Blodgett(LB) technique because quite uniform orientation could be obtained, which is one of the most important factors to affect to its optical characteristics. The resonance frequency and other electrical parameters at the parallel resonance state were measured using the impedance analyser(HP 4294 A). Also the morphological changes of dye molecules after UV irradiation were observed using AFM. The parallel resonance frequency and resistance by electrical equivalent circuit were decreased with the UV irradiation and these aspects are different from general mass adsorption process. Therefore the structural changes of dye molecules are being considered, that is, the aggregated molecules become dissociated. It indicates that the shifts of the resonance frequency and the others occurred without mass absorption.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1464-1468
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• 1999

Non-activated indolinobenzospiropyrans, 6-(p-substituted phenylazo)-1',3',3'-trimethylspiroindolinobenzopyrans(1-4) have been synthesized by the reaction of commercially available Fischer's base with 2-hydroxy-5-arylazobenzaldehyde (S1-S4). The arylazosalicylaldehydes were obtained from the diazocoupling reaction of substituted anilines with salicylaldehyde. The rate of spiro-ring formation from the open form of these nonactivated spiropyran derivatives at room temperature has been investigated utilizing the stopped-flow method de-veloped earlier. Half life times $(t_{1/2})$ of the ring-closure reaction in ethanol are about 0.3-14 seconds for the nonactivated spiropyrans examined. UV-Visible absorption spectral data of the open merocyanine form of nonactivated spiropyrans, which showed no chromotropism at room temperature, have also been obtained.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3125-3128
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• 2013

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.146.2-146
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• 1998

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.16-18
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• 1993

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권3호
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• pp.105-110
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• 2002

J-aggregates in the mutual mixing LB films of [6Me-DS]$_{1-x}$ [DO]$_{x}$,[DS]$_{1-x}$ [DO]$_{x}$ and [DSe]$_{1-x}$ [DO]$_{x}$ have been studied by optical absorption, fluorescence and surface pressure-area isotherms. In [6Me-DS]$_{1-x}$ [DO]$_{x}$ films, sharp J-band absorption and fluorescence of [6Me-DS] are linearly shifted to the longer wavelength for the replacement of [6Me-DS] by [DO]. According to the x, a smooth shift of the limited area has been cleared. In the [DS]-[DO] system, the J-band is enhanced at 1:1 composition and strong fluorescence is also observed. Also, the presence of phase separation was suggested in the [DSe]-[DO] system, because the absorption spectra were decomposed into [DSe] and [DO] spectra. On the other hand, in the pressure-area isothermal study, reduction in the molecular occupying area of monolayers has been clarified. This could be ascribed to the enhancement of molecular ordering in J-aggregates. These facts are also believed to reflect the most closely packed arrangement of chromophores in the merocyanine dye monolayers. Thus, it was confirmed that the interaction between mixed dye molecules and the CdC1$_2$+KHCO$_3$subphases affected the J-aggregates of the LB films. Also. it is thought that the J-aggregates are formed non-dimensionally in LB films, such as solution synthesized [DX:DO] assemblies on mixing.s on mixing.

• 한국염색가공학회지
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• 제27권4호
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• pp.270-274
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• 2015

Molecules always show broad absorption band envelopes, and this results from the vibrational properties of bonds. The width of an absorption band can have an important influence on the color of a dye. A narrow band imparts a bright, spectrally pure color to the dye, whereas a broad band can give the same hue, but with a much duller appearance. Typically, half-band widths of cyanine dyes are about 25nm compared to value of over 50nm for typical merocyanine dyes. Thus, cyanine dyes are exceptionally bright. The factors influencing the width of an absorption band can be understood with reference to the Morse curves. The width of the absorption band depends on how closely the bond order of the molecules in the first excited state resembles that in the ground state. We have quantitatively evaluated the "molecular structure-absorption band shape" relationship of dye molecules by means of Pariser-Parr-Pople Molecular Orbital Method(PPP-MO).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.352-353
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• 2007

The spectrum for $0_{\circ}$, $90_{\circ}$-polarized light coincides with the spectrum for non-polarized light and also with the spectrum was observed in the LB film deposited using a fresh solution. And, the formation and dissociation of J-aggregates, anisotropic behavior was no longer observed in the heat treated merocyanine dyes LB films. But, in the optical absorption spectra of same LB films by UV irradiation at room temperature, their were observed only dissociation of J-aggregates, that is decrease of absorbance peak without change spectral shape. On the other hand, in the case of optical absorption spectra of the LB films by the heat treatment at $70^{\circ}C$ in the air, both of the shifted absorption bands decay and a monomer absorption peak of about 530 nm appears instead.

• 폴리머
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• 제29권1호
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• pp.25-31
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• 2005

6-(파라헥실페닐)카보닐 스피로벤조피란(6-(p-hexyloxyphenyl)carbonyl spirobenzopyran, COSP)기를 포함하는 새로운 초산 셀룰로오스 유도체(CA-COSP)를 초산 셀룰로오스의 에테르화 반응에 의해 합성하고 이들의 물리적 특성과 광변색 특성을 조사하였다. COSP 치환도는 $^1H$-NMR과 UV 분광학적으로 확인한 결과 반응조건에 따라 셀룰로오스 내 잔류 수산기에 대하여 0.87~45.5%가 됨을 알 수 있었다. 얻어진 CA-COSP의 자외선 분광학 실험 결과 이 고분자는 자외선에 의해 메로시아닌(merocyanine) 구조로 변화하면서 무색에서 푸른색으로 변색하고, 가시광선 또는 열에 의해 다시 투명한 스피로피란(spiropyran)으로 돌아오는 가역적인 색변화가 일어남을 알 수 있었다. 색변화는 용액에서의 경우가 필름보다 빠른 특성을 보여주었으며, 극성용매 중에서는 메로시아닌의 안정성이 더 높아져서 스피로피란으로의 역반응이 더 느리게 일어남을 확인하였다. COSP를 CA-COSP에 혼합할 경우의 상용성을 COSP를 초산 셀룰로오스에 혼합할 경우와 비교하였다. 그 결과 순수한 초산 셀룰로오스의 경우 0.9 wt% 이상 혼합하면 상분리가 관찰되었으나, CA-COSP의 경우에는 48%까지 COSP를 혼합하여도 상분리가 관찰되지 않았다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1343-1348
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• 2014

A cholesterol-bridge-naphthopyran dyad (NP-MCB) was designed and synthesized. NP-MCB can readily self-assemble into gels under ultrasound-radiation in several organic solvents and the formed gels easily transfer to solution by heat. This reversible process can be repeated many times. Scanning Electron Microscopy results showed that the morphologies of all formed xerogels in different solvents have fibrillar microstructure. The gels formation was due to energy and pressure afforded by the ultrasonic process, resulting in formation of molecular hydrogen bonding and molecular aggregation. NP-MCB displayed the normal photochromism both in solution and gel states. The kinetic results confirm that the colored merocyanine in gels show a slower fading speed than that in solution due to the compact aggregation of NP-MCB molecules in gels. The xerogel film formed in polar gelling solvent had large surface wettability than that in nonpolar gelling solvent.