Glass disease
[4] Once damage has occurred it is irreversible, but decay processes can be slowed by climate control to regulate surrounding temperature, humidity, and air flow.
[7][8] The likelihood of degradation due to glass disease depends on the amount and proportion of alkaline compounds mixed with silica, and on surrounding conditions.
Exposure to higher levels of relative humidity during storage or display causes alkali to hydrate and leach out of the glass.
[9] Crystal, historic glass, or treasured family items should never be exposed to the high temperatures and water pressure of a dishwasher.
[10][11] Energy dispersive x-ray analysis (EDXA),[1][8] scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) can be used to study exchange reactions in different types of glass.
By quantifying and studying chemical structure and reactions at the near-surface layer, the mechanisms of glass disease can be better understood.
[14] This will help to stabilize the glass by reducing the surface pH, and by removing dust, soiling, and hygroscopic components that attract further moisture.
The presence of sodium or potassium ions in the alkali build up will increase the pH on the surface of the glass, causing it to become basic.
When examined closely at an angle with a low light, fine cracks like tiny silvery lines or shimmering rays, may be visible.
The works of modern glassmakers who experiment with their glass formulas, such as Ettore Sottsass, can also be at high risk for damage.
[9][17] Small ornamental glass beads were often made cheaply, using recipes with a high flux to silica ratio.
The combination of glass beads with other materials (cordage, fabric, leather, metal, bone, surface colorants, ceremonial substances, and kaolin) complicates deterioration and conservation of ethnographic objects.
The Corning Museum of Glass recommends washing with tap water (tepid, not hot[18]) and a mild (non-ionic[18]) conservation detergent.
Careful washing can remove surface deposits, restore the appearance of clearness to the glass, and help to slow further deterioration.
Because crizzling results from the reaction of components of the glass with water vapour, controlling humidity and temperature can slow its occurrence.
For example, the British Museum chose to conserve and display a Siberian shamanic apron made of leather, glass and other materials.
They weighed the likelihood that it would decay more quickly if shown against the desirability of making a unique object visible and the inevitability of its eventual degradation.
