Chemical composition of early modern and modern window glass from archaeological excavations in Prague‐Hradčany, Czech Republic

Abstract

A total of 101 fragments of the window rondels and fillings from four waste pits located in Prague‐Hradčany and dating to between 1500 and 1775 were analysed. In the sample set examined, ash‐based glass was found to be the most abundant (93 samples). The analysis also identified five fragments of non‐ash glass, that is, glass probably made with the addition of potash, two samples of sodium ash glass (containing halophytic plant ash used as an alkaline raw material), and one fragment of high‐lime low‐alkali (HLLA) ash‐based glass. The evolution of window glass composition in the Czech Republic is shown to differ in comparison with other European regions where the HLLA‐type predominates.