Porosity in ancient glass from Syria (c. 800 AD) using gas adsorption and atomic force microscopy

Gas adsorption and atomic force microscopy have been used to quantify and compare the porosity, surface area and surface characteristics of five samples from Raqqa in northern Syria dating to ca. 8th century AD. High-quality high-pressure liquid chromatography (HPLC) glass was also analysed to compare the results with these characteristics of modern glass. All five ancient samples were found to have some porosity across the microporous (up to 2 nm) and the mesoporous (2-50 nm) range. The reasons for this porosity are not entirely clear at present but are likely to be due to the manufacturing methods used, including the raw materials. A correlation was found between glass chemical composition (especially the total alkali) and pore size, inferring that the melting temperature is one of the parameters that affects the development of pores. The work in this paper presents the preliminary findings from the study of porosity in ancient glass.