Dr. Miriam Hiebert received her Ph.D. in Materials Science and Engineering in 2019 from the University of Maryland. After graduation she worked as a post-doctoral Fellow at the Smithsonian’s Museum Conservation Institute where she carried out analysis of glass plate images from the Photographic History collection at the National Museum of American History. She is now working the National Museum Natural History of on the development and execution of a pan-institutional glass condition survey across the Smithsonian.
Glass is often thought of as a very stable, unchanging material. That, unless you drop it, it will be around forever. This, however, is far from the truth. Glass undergoes a unique and insidious type of degradation. It interacts with the humidity in the atmosphere, swapping out some of its own components for water, forming a brittle layer that most will recognize as the white scum that forms on glasses that have been run through the dishwasher a few too many times. This degradation, referred to as glass alteration, happens slowly, taking decades if not centuries to be noticeable. For most glass, glass alteration doesn’t really matter – the object is likely to be dropped or lost before anyone notices a change. But for glass objects in museums, some of which have been around for millennia, and all of which are intended to last a lot longer, the slow time scale of alteration can become a problem.