Photochromic Performance of Fulgide on Disk as Data Storage Media

Abstract

t Department of Applild Chemistry, Faculty of Engineering, Shizuoka University; Hamamatsu-shi 432 Japan Photochromic fulgides, e. g.4-oxazolyl type [1 3 ] and 3-furyl type fulgide (4) and (5) were synthesized. And the optical fulgide disks were prepared by spin-coating metho d, and recorded with argon ion laser emitting at 514.5 nm. Fulgide[ 3J disk (fulgide content; 6.4 w t%) exhibited high C/N ratio (47 d B) from the read-out signal because of the high absorption coefficient of colored fulgide (26000 M-lcm-'). On the other hand, fulgide (5) di sk did not show enough C/N ratio for practical use, because of the low absorption coefficient (6200114-'cm-1). Recording power was dependant upon the quantum yield, and fulgide 5 3 disk which featured high bleaching rate needed lowest recording power (5 mW). Though fulgide [3] exhibited low quantum yield for bleaching (1.8 x10-4), it was possible to record on the disk. A nd the disk showed high read-out stability and record-erase cycle fatigue resistance.