DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click
HERE to register or log in.
Accession Number:
ADA183525
Title:
Far Infrared and Dielectric Relaxation Spectra in Supercooled Water and Water + Propylene Glycol Solutions.
Descriptive Note:
Technical rept.,
Corporate Author:
PURDUE UNIV LAFAYETTE IN DEPT OF CHEMISTRY
Report Date:
1987-08-01
Pagination or Media Count:
15.0
Abstract:
We report the first measurements of the far IR absorption in supercooled water, the extend the temperature range of study of the most interesting feature, and H bond stretching mode at approx. 200cm, to 85 C by incorporation of propylene glycol, PG, as solute. Low frequency dielectric relaxation measurements on a series of glass-forming PG water solutions spanning the ra ge 30-100 PG when fitted to the Vogel-Tammann-Fulcher equation suggest this resonance absorption mode may be the attempt frequency for the relaxation process. Comparison of the strengths of the two dissipation regions in the same absorptivity alpha units shows dielectric relaxation as a weak shoulder sliding, with changing temperature, on the alphakf gamma edge of the quasi-resonant absorption band. For most compositions, the dielectric loss spectrum is only weakly dependent or temperature, but as the composition approaches the edge of the glass-forming region, the spectral widths become strongly temperature-dependent due, evidently, to a clustering phenomenon which results finally in an unexpected liquid-liquid phase separation. Keywords spectra, dielectric relaxation, propylene glycol water solutions, phase separation, far infrared spectra.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
