Radiation-induced polymerization of glass-forming systems. III. Effect of melting point and glass transition temperature on the formation of the glassy phase

Abstract The general empirical rules about glass formation of organic compounds including monomers were studied. It was found that the difference of T m (melting point) and T g (glass transition temperature) was the most important factor in glass formation, that is, the glass‐forming property of organic systems, mono‐ or multicomponent, could be expressed as a function of T m and T m – T g at the cooling temperature −196°C. The glassforming property was further divided into four classes according to the relation between T m and T m – T g , and each class was related to several patterns in DTA curves. From these results it was clarified that the phases are completely or partially glassified depending on the different values of T m – T g in eutectic and noneutectic compositions. The overall phase diagrams covering the whole composition with the variation of T m and T g were determined, and they also supported the relationship between T m – T g and the glass‐forming property. The distinct glass‐forming property of binary systems with large molecular interaction was attributed to the great lowering of T m and elevation of T g in those systems. The effect of the number of components on glass formation was also studied; it was shown that if T m , T g , and Δ H (sum of heat of melting and of mixing) are given, the number of components necessary to glassification can be estimated.