{"title":"A multi-state barrier model for the multiple dielectric relaxations of bulk amorphous polymers and related glass-forming systems","authors":"Vittorio Rosato, Graham Williams","doi":"10.1016/0378-4487(81)80016-7","DOIUrl":null,"url":null,"abstract":"<div><p>The dynamics of a fluctuation model, broadly based on an earlier model of Bueche, is considered for the motion of a molecule in a glass-forming material. The molecule is assumed to occupy a number of local states in four equivalent manifolds and relaxes by motion between the local states and between manifolds. The dipole-moment correlation function, and hence the dielectric relaxation behaviour, is calculated for a range of relaxation parameters. Two general processes are found being (i) a family of ‘fast’ relaxation modes due to motion between the local states and (ii) a single ‘slow’ relaxation mode due to motion out of one manifold into adjacent manifolds. This pattern is qualitatively in accord with observations of and α processes in glass-forming systems but the observed α-processes are generally rather broader than a ‘slow’ single relaxation-time process which results from the present model.</p></div>","PeriodicalId":100049,"journal":{"name":"Advances in Molecular Relaxation and Interaction Processes","volume":"20 4","pages":"Pages 233-248"},"PeriodicalIF":0.0000,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0378-4487(81)80016-7","citationCount":"4","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in Molecular Relaxation and Interaction Processes","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0378448781800167","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 4
Abstract
The dynamics of a fluctuation model, broadly based on an earlier model of Bueche, is considered for the motion of a molecule in a glass-forming material. The molecule is assumed to occupy a number of local states in four equivalent manifolds and relaxes by motion between the local states and between manifolds. The dipole-moment correlation function, and hence the dielectric relaxation behaviour, is calculated for a range of relaxation parameters. Two general processes are found being (i) a family of ‘fast’ relaxation modes due to motion between the local states and (ii) a single ‘slow’ relaxation mode due to motion out of one manifold into adjacent manifolds. This pattern is qualitatively in accord with observations of and α processes in glass-forming systems but the observed α-processes are generally rather broader than a ‘slow’ single relaxation-time process which results from the present model.