The rates for nucleation (I) and crystal growth (U) for a lithium disilicat
e (Li2O . 2SiO(2), LS2) glass were determined, as a function of temperature
, using a new differential thermal analysis (DTA) technique. This technique
requires in situ nucleation and crystal-growth heat treatment of a small a
mount of powdered sample inside the DTA apparatus, which then are followed
by a DTA scan at a constant heating rate. The I and U values that have been
determined at selected temperatures for the LS, glass are in excellent agr
eement with those reported in the literature. The technique also has been u
sed to determine the concentration of quenched-in nuclei in LS2 glasses pre
pared from melts that have been quenched at different rates, which are in r
easonable agreement with those estimated from theoretical considerations. T
his new DTA technique is less tedious, requires a smaller amount of sample,
and is at least 10 times faster than the conventional methods that have be
en used to measure I and U, Also, no special sample preparation, other than
simply grinding and screening the glass to a particle size that is suitabl
e for use, is required in this technique, whereas grinding, polishing, or e
tching is required in conventional methods. The excellent agreement in the
I or U values that have been determined for the LS2 glass via the present a
nd conventional methods demonstrates the accuracy, validity, and usefulness
of this DTA method for rapid determination of the nucleation and crystal-g
rowth rates in glasses.