Fig. 2 also shows endothermic events associated to enthalpic relaxation related to physical ageing processes, at intermediate moisture content (i.e., 18–21%).
These are highly distinctive endothermic peaks that can be seen just when the heat capacity change related to Tg ends. At moisture contents higher than these values, only the Tg manifestation was observed, as samples
were in the rubbery state at the storage temperature for conditioning (25 ◦C).
Ageing events were also clearly seen (i.e., a very distinctive peak) in samples with 4.5% of CO (in samples with
moisture contents between 18 and 20), and 6.6% of CO (in sample with moisture content range of 13–17%).