IR transparent bulk-crystallized chalcogenide glasses purely containing nontoxic and excellent nonlinear optical crystallites AgGaGeS4 were fabricated through careful ceramization process of the as-prepared glasses with the composition 53GeS(2 center dot)47AgGaGeS(4) at a temperature of 350 degrees C for various durations. The second-order optical nonlinearity of bulk-crystallized chalcogenide glasses was discussed on the basis of Maker fringe theory. A large second-order optical nonlinearity (for lambda = 1064 nm) up to 5.79 pm/V, was evaluated in the IR transparent chalcogenide glass bulk-crystallized for 24 h. (C) 2008 Elsevier B.V. All rights reserved.