Glass Hydration: A Method of Dating Glass Objects

A new nondestructive method for dating or authenticating man-made glass is proposed, and the initial results of an exploration of the potential of this method are presented. The method is based on a relation between the age of a glass object and the thickness of the layer of hydrated glass on its surface, with the thickness of this hydrated surface layer being measured by means of the 15 N nuclear resonance depth profiling technique. A qualitative age scale is established for some common 19th- and 20th-century American glass.