Here's a nice factoid from it: > circa 1970 Accidental production of first glass bubbles at 3M plant in Guin, AL > circa 1975 Cryogenic research testing by G.

Here's a nice factoid from it: > circa 1970 Accidental production of first glass bubbles at 3M plant in Guin, AL > circa 1975 Cryogenic research testing by G. R. Cunnington and C. L. Tien at UC Berkeley