| dc.description.abstract | Dielectric relaxation studies were carried out
principally on some hydroxy compounds (e.g., phenols) and
some carboxylic acids in polystyrene (PS) matrices and,
in some cases, in compressed solids (CS). The hydroxy
compounds in PS showed at least one absorption each
corresponding to the molecular relaxation. In CS and,
in some cases, in PS, a second absorption process due to
the O-H group relaxation was observed in some of these
compounds. The relaxation parameters as well as the
Eyring activation parameters for both the molecular
relaxation and group relaxation were found to be significantly
influenced by hydrogen bonding in several cases.
In general, carboxylic acids showed two families of
absorptions. The common absorption process observed for
all the acid molecules was attributed to the 0-H group
relaxation in cyclic acid dimers which has to be preceded
by the breakage of hydrogen bonds in the cyclic structures.
The other absorption process for a number of the
acid molecules was attributed to the molecular relaxation
and/or segmental motion. In case of ester molecules a
common process due to O-R group reorientation was
observed. | |
