By utilizing a pH indicator having known color change characteristics, an accurate determination of the pH of a binder surface, and hence the amount of cure of a polycarboxylic acid based binder on the fiberglass fibers, can be easily determined for polycarboxylic binder based fiberglass materials used in insulation and composite applications. Based on these results, the manufacturing line used to make these bindered materials may be adjusted to ensure adequate curing at maximum efficiency while minimizing operating costs and reducing waste.