Short test of 3mm polycarbonate sheet dipped in hot water, comparing "reference" value using electrical tape with untreated surface. The tape is not fully opaque ( tested at 95%) but was applied as 2 layers thick.
ThermoView TV46 Fusion Recorded Image (attached)
Measuring at the instance of removal
The result is sufficient to conclude that the surface of the polycarbonate has similar emissive properties as 2 layers of electrical tape at the wavelength of the TV46