  Recent efforts to deal with the complexities of the liquid state,
particularly those of glassforming systems, have focused on the "energy
landscape" as a means of dealing with the collective variables problem [1]. The
"basins of attraction" that constitute the landscape features in configuration
space represent a distinct class of microstates of the system. So far only the
microstates that are related to structural relaxation and viscosity have been
considered in this paradigm. But most of the complex systems of importance in
nature and industry are solutions, particularly solutions that are highly
non-ideal in character. In these, a distinct class of fluctuations exists, the
fluctuations in concentration. The mean square amplitudes of these fluctuations
relate to the chemical activity coefficients [2], and their rise and decay
times may be much longer than those of the density fluctuations - from which
they may be statistically independent. Here we provide data on the character of
chemical order fluctuations in viscous liquids and on their relation to the
enthalpy fluctuations that determine the structural relaxation time, and hence
the glass temperature Tg. Using a spectroscopically active chemical order
probe, we identify a "chemical fictive temperature", Tchm, by analogy with the
familiar "fictive temperature" Tf (the cooling Tg). Like Tf, Tchm must be the
same as the real temperature for the system to be in complete equilibrium. It
is possible for mobile multicomponent liquids to be permanently nonergodic,
insofar as Tchm > Tf = T, which must be accommodated within the landscape
paradigm. We note that, in appropriate systems, an increase in concentration of
slow chemically ordering units in liquids can produce a crossover to fast ion
conducting glass phenomenology.
