Surface Durability of Optical Glass

JSGT 1953 V37 T249-T255

The surface durability of optical reticules was studied under high humidity by subjecting the samples of glass to cycles of surface fogging and clearing. The total transmission and the amount of scattered light of the weathered samples were measured by means of a photoelectric haze-meter, the relative amount of scattering being considered as a measure of the amount of haze or surface deterioration. The various types of optical glass including “crown,” “crown flint,” “borosilicate crown,” “dense barium crown,” “barium flint,” “light flint,” “dense flint” and “extra dense flint” were compared. Haze curves of each glass were shown, and possible reasons for the differences in surface durability were discussed. The haze-test results were compared with other types of durability tests.

H. E. Simpson