Synthesis of photochromic indolinespiropyrans
Photosensitive compositions for direct positive color photography
Color image forming method and particulate developer for developing electrostatic latent image Patent #: 5045420
ApplicationNo. 938044 filed on 11/12/1992
US Classes:430/345, Spiropyran dye or dye former252/586, Displaying color change430/962, RADIATION-CHROMIC COMPOUND548/402, Heavy metal or aluminum containing548/409Both rings which form the spiro are hetero rings
ExaminersPrimary: Bowers, Charles L. Jr.
Assistant: McPherson, John A.
Attorney, Agent or Firm
Foreign Patent References
International ClassesG03C 001/735
Foreign Application Priority Data1991-03-13 JP
AbstractThe object of the invention is to provide a novel compound exhibiting stable photochromism.The invention is directed to a transition metal-spirobenzothiopyran complex of the general formula ##STR1## wherein R1 for example be C1-20 alkyl; R2, R3, R4, R5, R6, R7 and R8 independently may mean hydrogen; Y means O or S; M may for example be Cr, and a process for producing the complex.