A number of United States Armed Forces specifications are used to qualify optical coatings. An early specification, Mil-C-675, was specifically designed for single layer antireflection coatings of magnesium fluoride on glass optical elements. In fact, it even calls out the range of thicknesses the coatings can have. In addition, however, it specified that the coated element should pass certain humidity, solubility, abrasion, and adhesion tests (Table B.1).
These environmental tests have been applied to a much broader class of coatings than originally intended by the authors of this specification.
Another specification, Mil-M-13508, was written specifically to deal with aluminum mirror coatings, which are typically less durable than a hard magnesium fluoride AR coating.
A third specification, Mil-STD-810, covers material testing in general and is not specific to optics. Some sections of this rather long document, however, codify tests that are suitable for performing accelerated degradation tests on optical coatings. Sections 507.2 ("cycled humidity") and 509.2 ("salt fog") are very rigorous tests that cause degradation in all but the most durable coatings.
Online access to SPIE eBooks is limited to subscribing institutions.