MULTIPLE OPTICAL MEMORY USING PHOTOCHROMIC SPIROPYRAN AGGREGATES

Multiple recording technology is particularly important for the high d ensity optical memory. Through investigating the aggregate-forming abi lity of the new photochromic spiropyrans, we have developed five novel spiropyrans, the aggregates of which have sharp absorption bands at d ifferent wavelengths. We have fabricated a recording medium stacked wi th the five kinds of aggregate layers and confirmed ten multiple optic al recording characteristics by combining the five multiple frequency recording with the recording by two mutually perpendicular linear-pola rized lights.