摘要:

A novel donor acceptor substituted sterically overcrowded alkene was synthesized and characterized. Photoisomerization experiments it showed that this system could be converted with high efficiency towards acisphotostationary state and although the reverse isomerization towards thetransstate was not as efficient this compound can function as a chiroptical molecular switch.

ISSN:1058-725X    

DOI:10.1080/10587250008023807

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A new class of polyisocyanates incorporating the 8-phenylmethylenebicyclo [3.2.1]octan-3-one chromophore through three different linkage patterns to the polymer backbone was synthesized. Photoresolution and photoracemization experiments were conducted to test its response to circularly polarized light (CPL). Irradiation of the polymers with CPL leads to the partial photoresolution of the bicyclicketone chromophore. This enantiomeric excess causes the polyisocyanate chain to favor one helical sense over the other. The handedness of the polymer chain can be switched with the sense of the circularly polarized light, leading to novel photoresponsive polyisocyanates.

ISSN:1058-725X    

DOI:10.1080/10587250008023808

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Photoswitchable redox-activated monolayers on electrode supports act as molecular electronic systems for the electronic transduction of recorded photonic information. Photoisomerizable monolayers assembled on electrodes may act as command interfaces for controlling interfacial electron transfer and thus act as interfaces for the amperometric transduction of photonic signals recorded by the monolayer. Photoswitchable biomaterials assembled on electronic transducers represent novel optobioelectronic systems. This is exemplified by the organization of a photoswitchable enzyme for the amplified amperometric transduction of photonic signals, and by the tailoring of reversible immunosensor systems.

ISSN:1058-725X    

DOI:10.1080/10587250008023809

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We present our work on data storage and characterization in photochromic materials, and have succeeded in recording data at a total of 26 overlapping layers. The effect of bit depth and bit size were investigated by varying exposure time of the sample to the laser pulses. Bit size and bit depth were found to increase with exposure time and optimizing their values would increase the density of the possible number of data stored in a photochromic medium.

ISSN:1058-725X    

DOI:10.1080/10587250008023810

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In photochemical processes, the reactant resides on an excited state potential energy surface and the products accumulate on the ground state. Thus the reaction path must have at least two branches: one located on the excited state and the other located on the ground state energy surface. The novel feature of photochemistry is the “funnel” region where the excited state reactant or intermediate is delivered to the ground state.

ISSN:1058-725X    

DOI:10.1080/10587250008023811

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Dihydroazulene(DHA)/vinylheptafulvene(VHF) equilibration is based on photochemical ring opening and thermal cyclization. Optical and non-linear optical properties of DHA/VHF are reported. Multimode switching, comprising both photo-redox and off/on-fluorescence switching, are investigated. DHA covalently attached to cellulose shows multifold switching. A concept for cyclic multistate switching is proposed based on biphotochromic compounds.

ISSN:1058-725X    

DOI:10.1080/10587250008023812

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The great interest in photochromic materials for high-density optical memory has been increased for the past decade. A super-low power readout method has been proposed to solve a problem about degradation of recorded information by readout process. About 106-time readout was demonstrated by the method. New high-density optical memory, a super-resolution disk with a photochromic mask layer, was introduced. The super-resolution method has enabled us to increase the recording density of conventional optical disks. Ultra-high density near-field photochromic memory as a new innovative storage technology was also discussed.

ISSN:1058-725X    

DOI:10.1080/10587250008023813

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

With 1999 marking the 100th anniversary of the discovery of organic photochromic compounds1, it is a fitting time to reflect back on commercial uses that have developed from this interesting class of organic compounds over the years. From the many applications that have been proposed, including security devices and optical memory storage, the one application that has achieved substantial commercial success is switchable lenses. Such lenses, based on inorganic photochromes (AgX), have been available since the mid 1960s, but it is only in the last 10 years that organic systems with acceptable performance have been available in the marketplace. From the mid 1980s until his sudden death in early 1998, John Crano lead the research effort at PPG Industries that developed the photochromic systems that have been commercialized by Transitions Optical Inc. under the name Transitions®.

ISSN:1058-725X    

DOI:10.1080/10587250008023814

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

There are two primary factors limiting the commercial success of photochromic (PC) plastics, the relatively short lifetime of the finished products and their high cost. We attempted to produce a PC masterbatch with superior stability so that:

ISSN:1058-725X    

DOI:10.1080/10587250008023815

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Spiropyrans(SP), spirooxazines(SO), chromenes(CH), and fulgides photo- and thermal degradation mechanisms are reviewed. For SO it is reported that thermal and photodegradation have common mechanism pathways. The reaction with free radicals results in adducts formation and loss of photochromic properties.

ISSN:1058-725X    

DOI:10.1080/10587250008023816

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor