According to all the reference books I've seen, almost nothing was produced during the war. Glass was made and sold in Murano up to and afterwards, but during each war, production all but shut down. Because of this, pre-war pieces made in the 1930s were sold post war in the mid 1940s and '50s. I believe this to be why, for instance, pre-war pieces were purchased and brought to America in the 1950s.
Laura