VMS Help SET, FILE, Qualifiers, /EXPIRATION_DATE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /EXPIRATION_DATE=date
       /NOEXPIRATION_DATE

    Requires read (R), write (W), and control access. Being the owner
    of the file is one way to get control access.

    Controls whether an expiration date is assigned to the specified
    files.

    Specify the date according to the rules described in the OpenVMS
    User's Manual or the online help topic DCL_Tips (subtopic Date_
    Time). Absolute date keywords are allowed. If you specify zero as
    the date, today's date is used.