Polyphosphazenes, effect substituent

JThe effect of the substituent on the properties of the polyphosphazenes is not fully understood. For instance, [NP(OCH ) ]n and [NP C CH. homopolymers are elastomers (8,29). Synthesis using lithium, in contrast to sodium, salts is claimed to produce rubber-like fluoroalkoxyphosphazene polymers (30). The presence of unreacted chlorine or low molecular weight oligomers can affect the bulk properties (31,32). Studies with phosphazene copolymers both in solution and in the bulk state (29,33-38) indicate a rather complex structure, which points out the need for additional work on the chain structure and morphology of these polymers. 

Optical Devices. Of most interest in this application are those studies related to the nonlinear optical effects in polyphosphazene derivatives bearing aromatic azo imits (217-219) and the photorefractive effect with pol5q)hosp-hazenes bearing carbazolyl substituents (220). Possible applications include optical switches, frequency doublers for lasers, holographic data storage, and real-time image processing. 

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