In Pike's cabin by the bed is an alcove which has a rather interesting inset panel above it. The producers of the CGI remastered series turned this into a window which is a shame, as its original function seems clear:
We could always say that it isn't a real window either, given how thin it makes the Enterprise's hull look. I like to think of it as a viewscreen that gives the impression of being a window so the crew members will feel less "cooped up". If this is the case, it could just as easily be this "relaxation light" as well.