These window panels came in a bulk buy and don't fit any of the accompanying windows. I would have dismissed them as not LEGO, except the greenness exactly matches other trans green elements. They are approximately 4 studs wide and 3 high, therefore they do not fit inside a frame of that size, and are too small for the next size up.
These glass panels are
Trans-Green Glass for Window 4 x 4 x 3 Roof
from 6940-1 - Alien Moon Stalker
they fit with