You can do that in Shader Mixer. My machine is rendering so I can’t check and the names could be wrong, but simply find the Utility->Variable[Fixed] brick and either drag it or double click it. The drop-down on it should read “Ci”, select “time” instead. Connect it to the opacity entry on the DAZ Default Material brick. If you need the fading to go in reverse, add a Mathematical->Binary brick, and insert it between the Variable[Fixed] and the DAZ brick. Connect the Variable to the second connector of the Binary brick. Type a “1” on the first input and select “Subtract”. “time” goes from 0 to 1 irrespective of how long your animation is, so if you need the fading to start on a specific frame it may be better to just duplicate the scene and devote the copy just to the fading animation.