Mechanical spectra of glass-forming liquids. I. Low-frequency bulk and shear moduli of DC704 and 5-PPE measured by piezoceramic transducers

We present dynamic shear and bulk modulus measurements of supercooled tetraphenyl-tetramethyl-trisiloxane (DC704) and 5-phenyl-4-ether over a range of temperatures close to their glass transition. The data are analyzed and compared in terms of time-temperature superposition (TTS), the relaxation tim...

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Bibliographic Details
Published in:The Journal of chemical physics 2013-03, Vol.138 (12), p.12A543-12A543
Main Authors: Hecksher, Tina, Olsen, Niels Boye, Nelson, Keith A, Dyre, Jeppe C, Christensen, Tage
Format: Article
Language:English
Subjects:
Approximation
Bulk modulus
Decoupling
Glass - chemistry
Liquids
Mathematical analysis
Phase Transition
Phenyl Ethers - chemistry
Shear
Shear viscosity
Siloxanes - chemistry
Spectra
Spectrum Analysis
Temperature
Terphenyl Compounds - chemistry
Time Factors
Transducers
Viscosity
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Summary:We present dynamic shear and bulk modulus measurements of supercooled tetraphenyl-tetramethyl-trisiloxane (DC704) and 5-phenyl-4-ether over a range of temperatures close to their glass transition. The data are analyzed and compared in terms of time-temperature superposition (TTS), the relaxation time, and the spectral shape parameters. We conclude that TTS is obeyed to a good approximation for both the bulk and shear moduli. The loss-peak shapes are nearly identical, while the shear modulus relaxes faster than the bulk modulus. The temperature dependence of this decoupling of time scales is constant over the temperature range explored here. In addition, we demonstrate how one can measure reliably the DC shear viscosity over ten orders of magnitude by using the two measuring techniques in combination.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4789946