Time resolved optical spectroscopy is used to investigate the rotational dynamics of anthracene, tetracene, anthanthrene, and anthracene derivatives in o-terphenyl and cis-polyisoprene. New experimental techniques allow the rotational correlation time to be measured over more than 12 decades in time. In both matrices, the reorientation of anthracene follows the temperature dependence predicted by the Debye-Stokes-Einstein relation. In o-terphenyl, good agreement is observed with dielectric relaxation measurements of the α- and β-processes. The relationship of these results to probe translational diffusion data is considered.

Time-resolved optical measurements of probe reorientation in orthoterphenyl have been performed. Rotational correlation functions have been measured from 100 ps to 1 ms for anthracene and anthanthrene, while correlation functions were observed over a narrower time window for 9-phenylanthracene and 9,10-diphenylanthracene. The rotational correlation time of anthracene follows the temperature dependence of η/T, indicating that anthracene rotation is well coupled to the dynamics responsible for the main glass transition. At temperatures above 30 °C, rotational correlation times depend upon probe size. In this region, orthoterphenyl behaves as a simple liquid. At temperatures near −5 °C, observed rotational correlation times are roughly independent of probe size. These results are consistent with the existence of domains of associated orthoterphenyl molecules. At lower temperatures, near and below the glass transition temperature, a partial reorientation of anthracene associated with the β process is observed. These results imply that the β process in orthoterphenyl involves the partial reorientation of most molecules rather than the total reorientation of a small fraction of the molecules.

Singlet and triplet transient grating experiments have been used to measure rotational correlation functions for anthracene and 9,10-dimethylanthracene in cis-polyisoprene from Tg+120 °C to Tg+20 °C. Over this temperature range, the rotational correlation time varies by seven decades and follows the temperature dependence of the bulk viscosity. The observed correlation functions are not consistent with predictions of the anisotropic rotational diffusion model. The observed correlation functions for anthracene are consistent with a change in the predominant axis for rotational diffusion as a function of temperature. At high temperatures, in-plane rotation occurs most rapidly, while at low temperatures rotation about the long axis predominates.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLocal segmental dynamics of polyisoprene in concentrated solutions and in the bulkPatrick D. Hyde, Mark D. Ediger, Toshiaki Kitano, and Koichi ItoCite this: Macromolecules 1989, 22, 5, 2253–2259Publication Date (Print):May 1, 1989Publication History Published online1 May 2002Published inissue 1 May 1989https://doi.org/10.1021/ma00195a044Request reuse permissionsArticle Views121Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (990 KB) Get e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTime-resolved optical study of the rotational mobility of small probe molecules in bulk polyisoprenePatrick D. Hyde and M. D. EdigerCite this: Macromolecules 1989, 22, 3, 1510–1512Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://pubs.acs.org/doi/10.1021/ma00193a093https://doi.org/10.1021/ma00193a093research-articleACS PublicationsRequest reuse permissionsArticle Views47Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLocal segmental dynamics of polyisoprene in dilute solution: solvent and molecular weight effectsDean A. Waldow, Brian S. Johnson, Patrick D. Hyde, M. D. Ediger, Toshiaki Kitano, and Koichi ItoCite this: Macromolecules 1989, 22, 3, 1345–1351Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://pubs.acs.org/doi/10.1021/ma00193a056https://doi.org/10.1021/ma00193a056research-articleACS PublicationsRequest reuse permissionsArticle Views157Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

A picosecond holographic grating technique has been used to observe the local segmental dynamics of anthracene-labeled polyisoprene in dilute hexane, cyclohexane, and 2-pentanone solutions. The transition dipole of the anthracene label lies along the chain backbone, assuring that only backbone motions are detected. The experimental observable, the orientation autocorrelation function of a backbone bond, is compared with theoretical predictions. The observed correlation functions are consistent with models proposed by Hall and Helfand and by Bendler and Yaris. The effects of temperature and solvent viscosity upon the local dynamics of polyisoprene are investigated. The activation energy for the observed local segmental motions is ~ 7 kJ/mole.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLocal segmental dynamics of polyisoprene in dilute solution: picosecond holographic grating experimentsPatrick D. Hyde, Dean A. Waldow, M. D. Ediger, Toshiaki Kitano, and Koichi ItoCite this: Macromolecules 1986, 19, 10, 2533–2538Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/ma00164a013https://doi.org/10.1021/ma00164a013research-articleACS PublicationsRequest reuse permissionsArticle Views82Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts