  Acoustical measurements, electron spin resonance, and Raman spectroscopy have
been employed to probe sulfur over the temperature range 80 to 180 C, which
includes the polymerization transition and the supercooled liquid state.
Acoustical properties (sound velocity, absorption and impedance) have been
studied with both longitudinal and transverse waves at frequencies between 500
kHz and 22 MHz. The results confirm that polymeric sulfur is a solution of long
chain molecules in monomeric solvent, and that the polymerization transition is
not a second order phase transition, as was proposed theoretically. Sulfur is a
viscous liquid, but not viscoelastic, both below and above the polymerization
transition temperature. It is shown that the classical Navier-Stokes theory is
not applicable to the sound absorption in liquid sulfur in the highly viscous
state.
