Seven methods (Voigt model, Maxwell model, operator equation, mechanical impedance function, creep curve, relaxation curve, and dynamic modulus function) of specifying viscoelastic behavior are discussed. A number of exact relations between these methods of specification are worked out in detail. The majority of these relations are simple enough to be of practical value although a few are too cumbersome. Approximate relationships between the creep curve, the relaxation curve, Maxwell model, and Voigt model are discussed; and numerical examples show the magnitude of errors introduced by the approximation to be small even in quite unfavorable cases. A consideration of the practical utility and physical meaning of the various methods of specification distinguishes between (1) those of general descriptive value and those of direct experimental value; (2) those useful in a phenomenological study of mechanical behavior and those more suited to a formulation of molecular theory. A summary of the present molecular theories is presented together with their interpretation in terms of the Voigt and Maxwell specifications.

1.
J. C.
Maxwell
,
Phil. Mag.
35
,
134
(
1868
).
2.
T.
Alfrey
,
Quar. App. Math.
2
,
113
(
1944
).
3.
F. D.
Murnaghan
,
Am. J. Math.
59
,
235
(
1937
).
4.
W. Voigt, Lehrbuch der Krystallphysik (Leipzig, 1928).
5.
K.
Bennewitz
and
H.
Rotger
,
Physik. Zeits.
40
,
416
(
1939
).
6.
W.
Holzmuller
and
E.
Jenckel
,
Zeits. f. Physik. Chemie
A186
,
359
(
1940
).
7.
W.
Kuhn
,
Zeits. f. Physik. Chemie
B42
,
1
(
1939
).
8.
T. Alfrey, Mechanical Properties of High Polymers (Interscience Publishers, Inc., New York, 1946).
9.
J. J. Thomson, Applications of Dynamics to Physics and Chemistry (London, 1888).
10.
E.
Wiechert
,
Ann. Chim. Phys.
50
,
335
(
1893
).
11.
A. P.
Alexandrov
and
Yu. S.
Lazurkin
,
Acta Physicochimica
12
,
647
(
1940
).
12.
T.
Alfrey
,
Quar. App. Math.
3
(July,
1945
).
13.
R.
Simha
,
J. App. Phys.
13
,
201
(
1942
).
14.
H.
Leaderman
,
Ind. Eng. Chem.
35
,
374
(
1943
).
15.
T.
Alfrey
,
J. Chem. Phys.
12
,
374
(
1944
).
16.
A. V.
Tobolsky
and
R. D.
Andrews
,
J. Chem. Phys.
13
,
1
(
1945
).
17.
R. F.
Tuckett
,
Trans. Faraday Soc.
38
,
310
(
1942
).
18.
R. F.
Tuckett
,
Trans. Faraday Soc.
40
,
448
(
1944
).
19.
R.
Simha
,
J. Phys. Chem.
47
,
348
(
1943
).
20.
R.
Simha
,
Ann. N.Y. Acad. Sci.
44
,
297
(
1943
).
21.
A. V. Tobolsky, R. E. Powell, and H. Eyring, The Chemistry of Large Molecules (Interscience Publishers, Inc., New York, 1943).
22.
S.
Bresler
and
J.
Frenkel
,
Acta Physicochimica
,
11
,
485
(
1939
).
23.
A. V.
Tobolsky
,
I. B.
Prettyman
, and
J. H.
Dillon
,
J. App. Phys.
15
,
380
(
1944
).
This content is only available via PDF.
You do not currently have access to this content.