Optical emission from proton-beam-irradiated solid deuterium near 800 nm has been studied after termination of the proton beam. The continuous red emission shows a residual intensity that persists over 30 min from termination of the beam. Optical flashes can also be thermally triggered over 10 min after termination of irradiation. Such triggered flashes are shown to quench the infrared absorption of Stark-shifted charge-induced features. Ultraviolet photons can stimulate this red emission after termination of irradiation with no measurable decrease in intensity for 40 min. The cause of this continuous emission and optical flashes is discussed in the light of these results.