Patents by Inventor Victoria E. Askew

Victoria E. Askew has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Photochromic spiroxazine compounds
    Patent number: 5446150
    Abstract: Photochromic materials which have a structure which includes a spiro-pyrrolidinebenzoxazine structure comprising a pyrrolidine part and a benzoxazine part and the benzoxazine part includes at least one mesomeric electron donating group chosen from amino and alkoxy moieties, the one or more mesomeric electron donating groups being linked to the 6' position via attachment to a conjugated system in which the unsaturated bonds forming the linkage are chosen from --C.dbd.C--, --C.tbd.C--, --C.dbd.N-- and --N.dbd.N--.
    Type: Grant
    Filed: December 2, 1993
    Date of Patent: August 29, 1995
    Assignee: Pilkington plc
    Inventors: Martin Rickwood, Sean D. Marsden, Victoria E. Askew