Found during Niku IIIP (1996).
Compositional analysis of this material by the Winterthur Museum Analytical Laboratory has shown it to be polymethyl methacrylate. First marketed in Germany in 1927, polymethyl methacrylate first saw large scale production by Rohm & Haas and DuPont in the United States in 1936 under the trade name Plexiglas. In Britain it was produced by ICI, Ltd under the tradename Perspex. According to sources at Rohm & Haas, pre-war use of Plexiglas was limited to aviation and, in colors, for the manufacture of jukeboxes. During the war the material was, of course, widely used in aircraft.
Two aspects of the collected artifact provide clues to its origin. First, it is 1/8 inch (.125) in thickness. Second, it has a uniform curvature which appears to be original to the sheet. Research to date has established that the thickness and curvature precisely match the specifications for the cabin windows of the Lockheed Model 10 at the time these windows were replaced in NR16020 (February 1937). Neither the thickness nor the curvature matches windows used in B-24 aircraft. (See “Part #40552” for a complete discussion of this artifact.)