Scottish Window Glass:
15th-19th Centuries AD
Relatively little work has been done on Scottish window glass, particularly in aspects of raw materials and methods of preparation. The first set of data, compiled with SEM-EDAX on freshly fractured surfaces, and deriving from C18th - 1C9th rural settlements (Loch Tay), but also castle sites, is now emerging.
Early window (broad) glass (blown to a cylinder and subsequently split) appears to be potash glass, reflecting the use of wood ash. Crown glass (blown but also spun) is rich in soda as well as potash. More common sheet, polished broad glass, appears to be made of both alkalis and alkaline earths.
SEM-BS image of Arbroath Abbey medieval glass showing crackled glass matrix of lime glass and small dendritic growth of Mn-rich oxides
(by kind permission of Dr R Coleman, then of SUAT, Perth).