These results can be clearly seen in Fig. 3,which shows the change of 2Pr value (Δ2Pr) depending on the total dose. The Δ2Pr was calculated by as follows: Δ2Pr = (2Pa − 2Pb) / 2Pb × 100.Where, 2Pb and 2Pa are the 2Pr value of the films before and after the irradiation, respectively. Depending on the total dose, the 2Pr value of the PTO films was just
changed in the range of less than 10%. In the case of PZT films, a large decline in the 2Pr value of about 35% was observed as the total dose increases from 0 kGy to 300 kGy. It was found that whether the films were pre-poled or not¸ the changing behavior of 2Pr value with the total dose is very similar in PTO and PZT. On the other hand, it was found that the 2Pr values measured from the non-pre-poled part of the films is ~10% lower overall than that measured from the pre-poled
part of the films at the same dose