Inventors:
Dan L. Fanselow - White Bear Lake MN
Assignee:
Minnesota Mining and Manufacturing Company - St. Paul MN
International Classification:
G03C 152
Abstract:
Photochromic aziridines of the formula ##STR1## wherein R. sub. 1 and R. sub. 2 separately are hydrogen, lower alkyl, phenyl, or ortho or para lower alkyl or lower alkoxy substituted phenyl, and together are alkylene having 4 to 7 carbon atoms inclusive, are coated onto a substrate to provide a microcrystalline deposit thereon preferably followed by application of a barrier coating which is substantially oxygen-impermeable. In this manner, a thermally stable optically erasable imaging medium is provided.