Amorphous molecular glasses categories

Linear crystalline polymers always contain a fraction of amorphous material. For this reason they are usually considered biphasic systems. They show the typical transitions of amorphous polymers (glass and secondary) but also the common transitions of crystalline polymers (polymorphic, order-disorder, melting). Mechanical and physical properties of this category of polymers depend on morphology and amorphous/crystalline ratio, but also on the molecular mobility of the amorphous phase. 

To understand the molecular basis for the glass transition, the various molecular motions occurring in an amorphous polymer mass may be broken into four categories. 

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