Crystallite theory, glass

The crystallite theory suggests that the properties of glasses in a specific system should be associated with the phase diagram for that... 

Attempts to describe the structures of amorphous solids date nearly 100 years back. In 1921, Lebedev developed the crystallite theory [2] according to which glasses are an agglomerate of microcrystallites, too small to be detected with (the then) conventional methods. Even though this theory did successfully explain some properties of glasses, it was strongly debated. 

Glass-forming systems other than silica have been examined. The fraction of three- and four-coordinated boron in borate glasses can be determined by nmr (29). Both nmr and x-ray diffraction (30) results led to the suggestion that the boroxyl ring is the structural unit of vitreous B203 (22,29). The intermediate-size boroxyl ring represents a compromise between the crystallite and the random-network theory (29) (see Analytical methods). 

---