Fractured mirrors from destructive tests performed from 1980 to 1985 were saved; this collection is unique in that it originated from naturally occurring flaws on window glass plate and mirror surfaces. Selected specimens will be analyzed using a scanning electron microscope to determine, among other observations: the general shapes of naturally occuring critical flows; differences between shapes and sizes of flaws occurring on the surfaces of new and weathered window glass plates; the differences between the critical flows for both types of specimens when tested in full scale under uniform loading, and when using the concentric rings tests; and the correlation between stress at failure and flaw size at various flow direction/stress direction relationships.
