Blends of azobenzene-containing polymers and molecular glasses as stable rewritable holographic storage materials

Abstract

In recent years the developments in computer technology have drastically accelerated. In order to handle the ever growing amount of data to be stored, an increase in the storage capacities of mass storage media is necessary. A promising approach is holography, where the storage capacity is greatly increased by using the entire volume instead of only the surface of the medium. Write-once media, which are mainly based on photopolymer systems, seem to be fairly advanced. For a rewriteable media, only few systems can meet the strict requirements for holographic data storage materials. Photoaddressable azobenzene-based polymer systems are the most promising candidates, however the photo-physical sensitivity of these materials has to be further increased. Low molecular-weight organic glasses with azobenzene moieties can also be used for reversible inscription of holographic volume gratings. They exhibit a faster response time than a comparable photoaddressable polymer due to a lack of chain entanglements. A new photochromic molecular glass with optimized physical and photo-physical properties is investigated as blending materials to improve the photochromic response of photoaddressable polymers. By doping this photochromic molecular glass into photoaddressable polymers we are able to combine the high stability of polymer systems with the fast response of molecular glasses, thus creating a system which has the advantages of both material classes.