Spin coupler

Photochromism is a reversible phototransformation of a chemical species between two forms having different absorption spectra [17-20], Photochromic compounds reversibly change not only the absorption spectra but also their geometric and electronic structures. The geometric and electronic structural changes induce some changes in physical properties, such as fluorescence, refractive index, polarizability and electric conductivity. When the photochromic compounds are used as spin couplers , the magnetic interaction can be controlled by photoirradiation. 

To realize the above-mentioned systems, we carefully chose suitable switching units and radical moieties. As an initial attempt, we employed l,2-bis(2-methyl-l-benzothiophen-3-yl)perfluorocyclopentene (9a) as a photochromic spin coupler (Scheme 9.2). Compound 9a is one of the most fatigue-resistant diarylethenes [21]. Nitronyl nitroxide was chosen for the spin source, because this radical is jr-conjugative. Thus, we designed molecule 10a, which is an embodiment of the simplified model 8a [37, 62]. 

Matsuda, K., Me, M. (2000b). Photoswitching of intramolecular magnetic interaction a diarylethene photochromic spin coupler. Chemistry Letters, 29, 16-17. 

MATERIALS. The polyimide used in this study, PI-2555 and PIQ-13 (polyimide isoindoloquinazolinedione) were obtained from duPont and Hitachi, respectively. PIQ coupler, an aluminum chelate primer, was also obtained from Hitachi. The primer and polyimides were applied by spin coating. Test substrates included metallized glass slides, metal sheet, and 3-inch diameter silicon wafers. 

Uses Emulsifier, coupler, lubricant, softener, and release agent for paper, agric. coupling agent and lubricant In syn. fiber spin finishes (textiles)... 

Waveguides consist of a thin layer of a high-refractive index material surrounded by/embedded in a low-refractive material. One way of making these layers uses of photolocking of a second component in a polymeric layer, followed by removal of this component from the unexposed area In this way, fiber optic sheet systems have been made as well as beam splitters, couplers, etc. In a typical example (Fig. 13) a dilute solution of polycarbonate, methyl acrylate and a photoinitiator in a solvent is spin-coated on a substrate, pattemwise exposed such that the methyl acrylate polymerizes in the exposed area and finally evaporation of unreacted monomer from the unexposed areas. 

The three dimensional refi active indices of the fi eestanding PANI films were characterized with a modified prism-wave guide coupler (Metricon PC-2010) at 1550nm. The technique was previously developed and tested on a range of different fi-eestanding and spin coated polymer films[7,8] In this work Nz is the refi active index along the optical symmetry axis, Ny is the refi active index perpendicular to the symmetry axis in the film plane, while Nx is the refi active index normal to the film... 

Nevertheless, the general idea of generating spin canying pol3Tadical polyions connected via /n-phenylenes (or other ferromagnetic couplers) has attracted considerable interest ( polaronic ferromagnet ) (20) (Fig. 3). 

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