چكيده لاتين :
The PMMA electrets were prepared by thermal polarization method. UV-vis absorption and thermally stimulated discharge current (TSDC) spectra have been recorded in PMMA electrets of 10 11m thickness. The PMMA electrets are polarized at 333 K with different polarizing fields. The observed TSDC and UV-vis spectra are the function of polarizing field. It has been found that absorption
decreases with increasing field. The TSDC peak (ex peak obtained at high temperature) is shifted towards lower temperature region with increasing field. The observed activation energy with the low temperature peak (\3 peak) is found to be varied between
0.21-0.55 eV, while for ex peak it varies from 0.50 to 0.91 eV. The TSDC peaks are explained on the basis of theoretical predictions; however, the decrease in band gap energy of PMMA electret could be explained on the basis of UV-vis absorption peak.
The configuration of UV-vis absorption in the region 200-900 nm gives the method of characterizing band gap energy. The dipolar and space charge polarizations are possible mechanisms to explain the TSDC in PMMA electrets. The optical micrographs distinguish the molecular structure of polarized and unpolarized (i.e., pristine) samples.
