Photothermoplastic recording

Nowadays, polymeric photoconductors may be used in electrophotography, microfilms, photothermoplastic recording, spatial light modulators, and nonlinear elements. The combination of photosensitivity with high quality electrical and mechanical properties permits the use of such materials in optoelectronics, holography, laser recording and information processes. The applications of the various types of polymers were reported in the final parts of the relevant items in the earlier sections. Here, we will briefly analyze the common features of photoconductive polymer applications. The separate questions of each type have been dealt with in some books and papers [3, 11, 14, 329]. 

AH attempts to develop photopolymers or photothermoplasts suitable for fast and reversible recording and read-out of volume-phase holograms, however, have not gained commercial appHcation. The most important characteristics of materials for holographic information recording are Hsted in Table 4 (158). 

When very high requirements are imposed on the dielectric characteristics of polymer materials (e.g., when they are used as recording layers in thermoplastic and photothermoplastic data recording), TROP is the most suitable polymerization procedure [18, 22, 23] in the case of catalytic polymerization, there is a need to remove traces of metals from the polymers. The molecular weight of the polymers synthesized by TROP can be controlled with advantage due to the use of regulating polar additives, for example, -hexyl alcohol in the polymerization of carbazolyl-containing monomers [22],... 

Application in photovoltaic cells has been suggested many times, but the low conversion efficiency and particularly the high UV instability of the polymers have prevented their commercial utilization. Several other possible applications have been reported in the literature, but none have been exploited commercially. Among them are photothermoplastic imaging [93], holographic recording [94] and optical switching devices [95]. 

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