Characterisation of amorphous solids the glass transition temperature

2 Characterisation of amorphous solids the glass transition temperature 

Storage above the critical relative humidity (RH) point (75%) results in sufficient plastici-sation of the glass transition such that the amorphous form becomes rubbery and is able to crystallise [32]. Therefore, if there is a chance that amorphous material is introduced into the samples as a by-product of physical processing or manufacture, it is imperative that a detailed understanding of the relative stability of the amorphous fraction introduced, as well as the extent of production, is imderstood. 

A more recent approach using DMA makes use of a materials pocket for powders, which is mounted in a flexural mode. This provides an easier method of determining the Tg of a powder, and whilst modulus values are non-quantitative, measurement of amorphous 

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