The surface hydration of soda-lime glass and its potential for historic glass dating

More than three decades ago the idea of using ambient water diffusion on manufactured glasses as an archeological dating method was proposed for historic period artifacts. In this study, we use infrared spectroscopy (FTIR) and secondary ion mass spectrometry (SIMS) to model water diffusion into the surface of two soda-lime glasses that differ principally in the alumina and magnesium content. Lower temperature hydration experiments (60-140 °C) were conducted and the surface diffused water was measured by infrared absorption, transflectance, and reflectance spectroscopy to establish the diffusion coefficients and activation energies, and to investigate the change in glass surface structure with time at a constant temperature. SIMS was also used to document water diffusion within a sample recovered from a 19th century archeological slave quarters at Thomas Jefferson's Monticello plantation in Virginia, USA.