  A simple monatomic system in two dimensions with a double-well interaction
potential is investigated in a wide range of temperature by molecular dynamics
simulation. The system is melted and equilibrated well above the melting
temperature, and then it is quenched to a temperature 88% below the melting
temperature Tm at several cooling rates to produce an amorphous state. Various
thermodynamic quantities are measured as a function of temperature while the
system is heated at a constant rate. The glass transiton is observed by a
sudden increase of the energy and Tg is shown to be an increasing function of
the cooling rate in the preparation process of the amorphous state. In a
relatively-high temperature region, the system gradually transforms into
crystals, and the time-temperature-transformation(TTT) curve shows a typical
nose shape. It is found that the transformation time to a crystalline state is
the shortest at a temperature 14~15% below the melting temperature Tm and that
at sufficiently low temperatures the transformation time is much longer than
the available CPU time. This indicates that a long-lived glassy state is
realized.
