TA I
NSTRUMENTS
TGA 2950 B–53
Hi-Res
TM
Option
can be used to customize a method for a par-
ticular material by allowing different ramp and/
or isothermal segments to be used for each tran-
sition region without regard to specific tempera-
ture limits. Abort segments can be used to
control data storage so that file size is minimized
by turning off storage or increasing sampling
interval during baseline sections of a scan.
Abort segments provide a convenient mecha-
nism for shortening experiments after the data of
interest has been collected. For example, if a
heating ramp is used to analyze a material which
has two weight losses and the only data of
interest is the percent weight loss during the first
transition, then an abort segment can be used to
terminate the ramp after the beginning of the
second weight loss by specifying a “%” limit
condition. This is particularly useful for Hi-
Res
TM
ramps because the reduced heating rate
during a weight loss causes the majority of the
transition to occur during a very narrow tem-
perature range, making termination by final
temperature difficult to predict.
Stepwise
Isothermal Heating
Another useful TGA technique which can be
implemented with abort segments is transition-
controlled stepwise isothermal heating. This
process consists of heating a sample via a ramp
segment until a certain rate of weight change is
detected, and then switching to an isothermal
segment to hold constant temperature until the
transition has completed. Then the sample
heating is continued until the next transition is
detected, whereupon, isothermal holding is
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