Active Standard: C148 - 12
Provide clarification to a sentence in Section 7.1, which currently states Each disk shall have a nominal retardation at the calibration point, 6.4 mm (0.25 in.) from the outer circumference of the disk, corresponding to not less than 21.8 nm nor more than 23.8 nm of optical retardation. The source of confusion is that these disks are generally mounted in a frame which covers up the glass edge such that it is not possible to measure the required 6.4 mm from the edge without removing the disk from the frame.
KeywordsAnnealing strain; Glass containers; Polariscopic examination;