Do airlines have microwave ovens on their aircraft? I thought not, but not sure the reason why.
As vctenderness stated they certainly on the 747 100s. They were always used in 1st class and would annoy the passengers when crew used to slam the door shut especially after manually whipping a tray of eggs and scrambeling them. The black cherry ice cream which used to be stowed in a dry ice box always got defrosted before service, unless the galley girl forgot about it and when the door opened it poured out like a purple river