Spiropyran optical switch

Scheme 5.3 A spiropyran optical switch turns different colours under different conditions.

We have also demonstrated self-held ultrafast parallel optical switching based on the same geometry and using photochromic compounds instead of phthalocyanines [81-84], Absorption spectra of spiropyran derivative (SP) dispersed in polystyrene with a weight ratio of 1 10 are shown in Fig. 28 before and after UV irradiation for 5 sec. Strong absorption in the visible region due to photomerocyanine (PM) can be held for a long time and be reverted to that of... 

Seefeldt B, Kasper R, Beining M et al (2010) Spiropyrans as molecular optical switches. Photochem Photobiol Sci 9 213-220... 

Practical applications of photochromism at first (ca. 1955-70) concentrated on the spiropyrans, and especially on BIPS compounds, because of their ready availability, photosensitivity, convenient thermal fade rates, and good color contrast when perceived by the human eye. However, applications in which the dye was required to cycle very many times (e g., an optical binary switch for a photochemical computer memory) or be irradiated continuously (e g., sunglasses, vehicle windshields) were impractical because of the rapid fatigue of these dyes.196... 

Perhaps the most promising materials for all-optical write-read-erase switches are systems in which ultraviolet irradiation induces ring opening. One of the most studied systems are spiropyrans in which writing and nondestructive reading are based on successive two-photon and one-photon processes [46, 205 209]. 

Chiroptical molecular switches (photochromic compounds among them dihetarylethenes, fulgides, and spiropyrans permitting undestructive read-out of information using change of optical rotation 00CRV1789. 

A more complicated optically triggered molecular switch based on spiropyran (5.16) responds to chemical and optical inputs and produces an optical output (Scheme 5.3). Colourless spiropyran (5.16a) does not show any absorption at wavelengths greater than 400 nm. It switches to a purple merocyanine chro-mophore (5.16b, = 563 nm) upon irradiation with UV light. The merocyanine... 

Wen G, Yan J, Zhou Y, Zhang D, Mao L, Zhu D (2006) Photomodulation of the electrode potential of a photochromic spiropyran-modified Au electrode in the presence of Zn2- - a new molecular switch on the electronic transduction of the optical signals. Chem Commun 2006(28) 3016-3018... 

Plaquet, A, Guillaume, M., Champagne, B., Castet, F., Ducasse, L., Pozzo, J.L., and Rodriguez, V. (2008) In silico optimization of merocyanine-spiropyran compounds as second-order nonlinear optical molecular switches. Rhys. Chem. Chem. Phys., 10, 6223-6232. 

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