IR-transparent chalcogenide glass-ceramics were fabricated through a careful ceramization process of the as-prepared 65 GeS(2) x 25 Ga(2)S(3) x 10 LiI glasses at a temperature of 403 degrees C for various durations. Owing to the precipitation of Li(x)Ga(y)S(z) crystals with a Ga(2)S(3)-like structure, clear second-harmonic generation was observed in the sample crystallized at 403 degrees C for 60 h, which has a greatly improved resistance to environmental impairment. Additionally, it is found that the shorter crystallization process (< or = 60 h) contributed to the enhancement of Li(+) ionic conductivity, whereas a longer heat-treatment (80 h) would impair that of the glass-ceramics. The micro-structural origin of these varied properties was elucidated in detail. The corresponding results will be of benefit for the optimization of designed transparent chalcogenide glass-ceramics with improved thermo-mechanical properties, a permanent second-order optical nonlinearity, or a well-enhanced ionic conductivity for application in amorphous solid electrolytes.