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Laser light scattering studies of bulk polymers in the glass transition regime
Author(s) -
Jamieson A. M.,
Simha R.,
Lee H.,
Tribone J.
Publication year - 1981
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760211416
Subject(s) - glass transition , relaxation (psychology) , materials science , polystyrene , polymer , amplitude , laser , scattering , methacrylate , chemical physics , exponential decay , light scattering , coupling (piping) , dynamic light scattering , molecular physics , condensed matter physics , optics , composite material , nanotechnology , physics , copolymer , psychology , social psychology , nanoparticle , nuclear physics
The application of laser light scattering techniques to characterize the structural and dynamical properties of bulk polymers near the glass transition temperature is reviewed. Preliminary results of a study of poly(n‐butyl methacrylate) are presented. As in an earlier study of atactic polystyrene, the results suggest the coexistence of two relaxation mechanisms near T g : a fast, single exponential decay; a slow process characterized by a wide distribution of relaxation times. The slow relaxation mechanism is evidently the main‐chain glass transition process; it appears possible that the fast decay is a manifestation of side‐chain motion. However, in contrast to the polystyrene system where the fast mechanism is always of small amplitude in the temperature range amenable to study ( T g < T < T g + 40°), the fast mechanism in the poly(n‐butyl methacrylate) system exhibits a sudden transition to high amplitude (∼50 percent of the total observable relaxation amplitude) at T ∼ T g + 30°. At this point therefore, we suggest that a strong resonant coupling of the fast process with the slow relaxation is occurring.