Photochromic polymers-optical data

Polymer-based photochromic systems have been studied extensively and are attractive in terms of practical applications because of their advantages of stability and processability. A number of reviews and articles dealing with various aspects of photochromic polymers and photoactive biomaterials have been published. 68 Chiral photochromic peptides are discussed in Chapter 13, and photochromic liquid crystals and polymers for holographic data storage and nonlinear optics have been reviewed. 69 Specific stereochemical effects in chiral photoresponsive polymers include ... 

PHOTOCHROMIC POLYMERS FOR OPTICAL DATA STORAGE AZOBENZENES AND PHOTODIMERS... 

This chapter discusses photochromic azobenzene polymers and photochromic molecules capable of undergoing photodimerization as materials for potential use in optical data storage applications. A brief introduction to photochromism, including recent examples of some photochromic systems, other than azobenzenes, based on variety of applications is presented at the outset. Thereafter, we shall focus on azobenzene photoaddressable polymers (PAPs) and [4 + 4]-photocycloaddition as materials for ultrahigh capacity optical data storage. 

We shall now embark on the main focus of this chapter photochromic azobenzene polymers and photochromic materials capable of undergoing photodimerization for potential use in optical data storage applications. Herein, the photochromic polymers described are those in which the photochromic molecule is covalently linked, either as part of the main chain or as a side-chain, to the polymeric system. 

Photochromic polymers have played a pivotal role in the development of novel materials for optical data storage. Advances in holography have benefited from early research into PAPs. Although not based on PAPs, the first commercial holographic data storage devices are now available. 

These exceptional characteristics have been used later in several interesting applications. An elastic polymer film containing the same MV2 + salts as part of the main chain was found to be photochromic and results indicate that data can be written optically X > 365 nm) and erased thermally [212]. The photo-chromism was also observed in monolayer assemblies (Langmuir-Bloodgett films) made of mixtures of N,N hexadecyl-4,4 -bipyridinium salts of TFPB-and arachidic acid [213, 214, 215]. 

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