The time-resolved spectral output of pulsed DF and DF-CO2 chemical lasers initiated by fast electrical pulses has been investigated. Short-pulse electrical initiation of the D2+F2 mixture in the high-pressure DF-CO2 laser results in prompt laser emission from both DF and CO2 molecules in addition to the usual more energetic, but delayed, CO2 emission. Studies of the time correlation of the vibrational-rotational transitions observed in the DF and DF-CO2 systems provide evidence that the transfer of energy from DF (v?4) to CO2 involves transitions in which the rotational level change in DF is greater than one.