When I was a kid, a lady I knew turned her clear glass baking dishes a beautiful violet in color by placing them on her roof in the searing heat of the summer. When she took them down, however long later, they were a stunning electric violet in hue.
I put a clear glass Pyrex baking dish on the roof a year ago in the beginning of the long, hot summer and it has not changed color like hers did. Anyone know about this and how long should a piece be left out? Ever heard of it before? Should it be regular glass?