  We report new laboratory studies of the radiation-induced destruction of
glycine-containing ices for a range of temperatures and compositions that allow
extrapolation to Martian conditions. In-situ infrared spectroscopy was used to
study glycine decay rates as a function of temperature (from 15 to 280 K) and
initial glycine concentrations in six mixtures whose compositions ranged from
dry glycine to H$_2$O + glycine (300:1). Results are presented in several
systems of units, with cautions concerning their use. The half-life of glycine
under the surface of Mars is estimated as an extrapolation of this data set to
Martian conditions, and trends in decay rates are described as are applications
to Mars's near-surface chemistry.
