Multifunctional chromophores

Also, polymers that contain carbazole moieties in the backbone with two acceptor groups as multifunctional chromophores were synthesized. The sytheses were carried out by a Knoevenagel polycondensation of divinylcarbazoles with bis(cyanoacetate)s using 4-(N,N -dimethyl)pyridine as a base. Second-order nonlinear optical properties of the polymers were confirmed by second harmonic generation. The photorefractive optical gain of these polymers was demonstrated to be high. 

These compounds are multifunctional additives. They can act as heat stabilisers, radical traps, decompose hydroperoxides, UV absorbers, etc. (iv) UV absorbers. This is the largest class of UV stabilisers. They work on the same principle as sun-screen lotions they contain chromophores that can absorb light in the 280-400 nm region and release the excess energy as heat and not high-energy radiation. They must be stable under processing conditions and should not react with the polymer nor decompose with UV radiation. 

CTC-HC1 is the HC1 salt of amphoteric CTC it is multifunctional with two chromophores. It is a para-chlorophenol with an ot,3-unsaturated ketone in conjugation. 

This account has summarized several of our approaches to the preparation of electric-field-aligned chromophoric polymers for second order NLO applications. Molecular design has been employed wherever possible to arrive at structures that probe particular aspects of the polar orientation issue. The rich variety of accessible organic structures has enabled us to consider the orientation problem from a variety of points of view, and to indicate by example the manner in which multifunctional organic synthesis may play a role in the fabrication of oriented materials. 

Nonlinear optical phenyldiazo chromophores, (II), and (IE), were prepared by Gharavi [4] and Lindsey [5], respectively, and used as multifunctional optical switches. 

Multifunctional materials will play an important role in the development of Photonics Technology. This paper describes novel multifunctional polymeric composites for applications in both active and passive photonic components. On the molecular level, we have introduced multifunctionality by design and synthesis of chromophores which by themselves exhibit more than one functionality. At the bulk level, we have introduced the concept of a multiphasic nanostructured composites where phase separation is controlled in the nanometer range to produce optically transparent bulk in which each domain produces a specific photonic function. Results are presented from the studies of up-converted two-photon lasing, two-photon confocal microscopy, optical power limiting, photorefractivity and optical channel waveguides to illustrate the application of the multifunctional optical composites. 

It was shown that the thermal stability of conventionally formed polyimide polymers and copolymers (bearing nonlinear optical chromophores) is adequate for numerous device applications. There is a problems, however, with doped systems in that they tend to undergo phase separation. This limits the amount of the nonlinear optics chromophore that can be incorporated into the system. To try and make doping unnecessary, multifunctional polymers were synthesized that contain all the necessary components. One limitation of this technology, however, is the small nonlinear optical response (r33) values for many such poiyimides. This is not true of all of them. 

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