Modern Glass' 



By S. Donald Stookey 



Corning Glass Works, Corning, N.Y. 



[With 3 plates] 



A NEW world is suddenly unfolding to the startled glass teclinolo- 

 gist as he gazes into his 6,000-year-old crystal ball. As his eyes 

 gradually adjust to seeing in molecular detail the familiar transparent 

 solid turns out to hold a frozen mass of hidden fairy-tale princesses, 

 powerful sleeping giants and unknown creatures of all kinds, con- 

 densed to molecular size and trapped in an unexplored labyrinth ; each 

 waiting to be brought to life by the proper magic word. 



In more practical language, we are learning that glass consists 

 literally of chemical species in a frozen state of suspended animation, 

 somewhat as free radicals are trapped by freezing them. By using the 

 proper catalyst — which may be high-energy radiation or internally 

 precipitated colloids or heat, or a combination of these — a really aston- 

 ishing variety of electronic, chemical, and physical changes can be 

 initiated and controlled, resulting in a multitude of new materials. 

 Some of the current discoveries are completely reversing traditional 

 concepts. For example : 



Glass strengthening techniques now in the laboratory may soon 

 change our traditional concept of glass as fragile and brittle to one 

 that's strong and flexible. 



Long known as an electrical insulator, glass in some of its new 

 forms becomes an electronic conductor. 



Distinguished from most other solids by its noncrystalline amor- 

 phous structure, glass now is found to be a perfect medium for 

 controlled crystallization, and has become the spawning ground for a 

 growing number of unique new crystalline materials — as shown in 

 plate 1, for example. 



Famous for its impermeability to liquids and gases, high silica glass 

 has been found to be selectively permeable to the smallest gas mole- 

 cules such as helium, neon, and hydrogen ; it can be used as a molecular 

 sieve. 



* Reprinted by permission from International Science and Technology, No. 7, July 1962. 



323 



