NEUTRON-SCATTERING FROM VIBRATIONS AND RELAXATIONS IN AMORPHOUS POLYMERS

被引:6
作者
BUCHENAU, U
机构
[1] Institut für Festkörperforschung, Forschungszentrum Jülich, Jülich, D-52425
来源
PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES | 1995年 / 71卷 / 04期
关键词
D O I
10.1080/01418639508238569
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Recent neutron scattering investigations of amorphous polymers in the meV range are reviewed. They reveal several new results: (i) the low-frequency vibrations of the boson peak shift to lower frequencies with increasing temperature, (ii) a change in the atomic motional behaviour occurs at a crossover frequency of several tenths of a meV, corresponding to a relaxation time of about two picoseconds and (iii) the fast picosecond relaxation, supposed to be a typical feature of the undercooling liquid, has been found in some polymers far below the glass transition. A possible explanation for these findings is a crossover from more or less damped vibrations at high frequencies to low-barrier relaxations at lower-frequencies, The concept can be quantified in terms of the vibration-relaxation model, a simplified classical version of the soft-potential model for glasses.
引用
收藏
页码:793 / 807
页数:15
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