  We consider the effect of droplet excitations in the random first order
transition theory of glasses on the configurational entropy. The contribution
of these excitations is estimated both at and above the ideal glass transition
temperature. The temperature range where such excitations could conceivably
modify or `round-out' an underlying glass transition temperature is estimated,
and found to depend strongly on the surface tension between locally metastable
phases in the supercooled liquid. For real structural glasses this temperature
range is found to be very narrow, consistent with the quantitative success of
the theory. For certain finite-range spin-glass models, however, the surface
tension is estimated to be significantly lower leading to much stronger entropy
renormalizations, thus providing an explanation for the lack of a strict
thermodynamic glass transition in simulations of these models.
