Change dielectric function during

Figure 10 Change in dielectric function during electrochemical deposition.

It is important to first identify the segmental dynamics of an amorphous polymer melt, and if possible, observe any changes in the amorphous phase mobility during crystallization. As an example of such measurements, changes in the dielectric loss and dielectric constant in the frequency domain as a function of crystallization time at 22°C are presented in Figure 9.10. Short-time frequency sweeps were taken from 100 Hz to 1 MHz (the duration of a frequency sweep is lmin and much shorter than the time-scale of the crystallinity changes occurring). The curve at f = 0 corresponds to the fully amorphous polymer that was quenched prior to crystallization. As crystal-... 

The temperature-modulated mode of operation has been well known for many decades in calorimetry [33], but became well established only during the 1990s, when commercial DSC was modified this way [34], The idea is to examine the behavior of the sample for periodic rather than for isothermal or constant-heating-rate temperature changes. In this way it is possible to obtain information on time-dependent processes within the sample that result in a time-dependent generalized (excess) heat capacity function or, equivalently, in a complex frequency-dependent quantity. Similar complex quantities (electric susceptibility, Young s modulus) are known from other dynamic (dielectric or mechanical) measurement methods. They are widely u.sed to investigate, say, relaxation processes of the material. 

---