Patents by Inventor Georges Gerard Evens

Georges Gerard Evens 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 polycondensates
    Patent number: 4026869
    Abstract: Linear photochrome polycondensates of the polyester type are described which contain spiropyran photochromic groups as an integral part of the main polymer chain, have a glass transition temperature lower than 120.degree. C and possess photochromic properties at or above their glass transition temperature.Manufacture of stabilized photochromic images by exposing a layer of the photochromic polycondensate at a temperature at least equal to the glass transition temperature of the photochromic polycondensate and immediately cooling the thus exposed layer below the glass transition temperature.
    Type: Grant
    Filed: July 21, 1975
    Date of Patent: May 31, 1977
    Assignee: AGFA-GEVAERT, N.V.
    Inventors: Georges Gerard Evens, Georges Joseph Smets