For material setup, use emissive texture with color tint, and by changing that color towards black, you can change its fading. Make sure you don’t recreate pc.Color on each update, but have one for each meshInstance pre-created.
In order to fade any specific mesh rather whole material, use this method:
var fade = 0.5;
color.set(fade, fade, fade);
meshInstance.setParameter('material_emissive', color.data);