As shown in Fig. 9, the glass transition temperature (Tg) measurements
performed using AFM confirmed the offset of Tg to lower
temperatures (from 220 C to 160 C after 60 h of irradiation). A
good agreementwas found with the modifications of tan d resulting
from exposure. AFM measurements in nanoindentation mode were
also performed. Table 3 gives the values of the nano-hardness and
Young’s modulus as a function of irradiation time, and compares
these values with the Young’s modulus obtained by DMTA.