Dielectric relaxation of polystyrene doped with polar DR1 molecules
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Дата
2004
Науковий керівник
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Видавець
Одеський національний університет імені І. І. Мечникова
Анотація
Four relaxation processes identified in polystyrene containing 2 wt % of DR1 chromophore
were studied by the dielectric spectroscopy in the frequency range from 1 Hz to
1 MHz at constant temperatures from 30 to 130 °С and by thermally stimulated depolarization
current measurements at sub-zero temperatures down to —160 °С. Hamon’s transformation
of isothermal depolarization currents were also performed to give information on
dielectric relaxation at infra-low frequencies. It has been found that distribution of relaxation
times related to a relaxation becomes wider due to presence of dye molecules, while
both the dielectric constant and the dielectric strength increase. Considerable narrowing
of the loss peak was observed with increase of temperature indicating that the PS/DRI
system is not the thermoreologically simple one and temperature-time superposition principle
is not applicable above glass transition where the temperature dependence of the
relaxation time obeys Williams—Landel—Ferry law. It has been found that Arrenius law
is valid below glass transition.
Опис
Ключові слова
spectroscopy, chromophore, relaxation, temperature
Бібліографічний опис
Фотоэлектроника = Photoelectronics