On the basis of a kind of zinc phosphate oxynitride glass matrix with a broadband blue light, a series of manganese single-doped glasses were obtained. A broader red emission with the higher intensity belonging to the Mn2+ ion was observed in this glass matrix. The mechanism of the emission from Mn2+ ions was clarified through Mn3+ as an "energy acquisition probe" to replace complex dynamic luminescence discussion, which was a fit explanation for the differences in luminescence behavior of Mn ions in prepared glasses at different degrees of redox. The research results indicated that the prepared manganese-doped glass was a potential candidate as phosphor-converted white-light-emitting diodes. An encapsulated white-light-emitting diode device based on this glass with 276 nm ultraviolet chip was achieved. It showed the CIE values of (0.33, 0.35), high CRI (Ra = 86), and low color temperature (5228 K).