Glass Annealing And Method

The method of determining the degree of anneal or compacting of a piece of glass of a known composition comprising subjecting the piece of glass and a test piece of glass of substantially the same composition but of a known maximum index of refraction when completely annealed or compacted to an annealing cycle, determining the index of refraction of the test piece after passing through the annealing cycle to determine its degree of anneal or compacting by comparing the index of refraction of the test piece at the com.