POLY IR® 1	POLY IR® 2	POLY IR® 3	POLY IR® 4	POLY IR® 5	POLY IR® 6	POLY IR® 7
Index of Refraction
visible (sodium D line)	1.52	1.53	1.50	1.53	1.425	1.49 at 1 µm	1.53
8-14 µm	1.53	1.54	-	1.54	-	-	1.54
beyond 15 µm	1.48	1.48	1.50	1.48	-	-	1.48
Tensile modulus (103 PSI)	14-38	60-180	165-225	60-180	150-300	350-450	60-180
Flexural modulus (103 PSI)	8-60	100-260	170-250	100-260	170-250	390-470	100-260
Hardness	D40-50 (Shore)	D60-70 (Shore)	R85-110 (Rockwell)	D60-70 (Shore)	R80 (Rockwell)	M80-100 (Rockwell)	D60-70 (Shore)
Thermal expansion (10-5/°C)	10-20	11-13	6-10	11-13	4.5-7	5-9	11-13
Service Temperature, °C	65	100	120	100	70*	80	100
Effect of sunlight	crazes rapidly	none	crazes rapidly	slight	none	none	crazes rapidly
Effect of weak acids	little	very little	none	very little	none	none	very little
Effect of strong acids	attacked by oxidizing acids	attacked by oxidizing acids	attacked slowly by oxidizing acids	attacked by oxidizing acids	none	attacked by conc. oxidizing acids	attacked by oxidizing acids
Effect of weak alkalies	little	very little	none	very little	none	none	very little
Effect of strong alkalies	little	very little	very little	very little	none	attacked	very little
Effect of organic solvents	little	little below 60°C	little below 80°C	little below 60°C	slight	sol. in ketones, esters, and some hydrocarbons	little below 60°C
Physical Properties of POLY IR® Materials
*POLY IR® 5 material becomes flexurally weak above 70°C, i.e., its heat deflection temperature is very low even for the small stresses normally encountered in mounted lenses. Unless you take special precautions to avoid such stresses, we do not recommend that POLY IR® 5 material be use above 70°C even though its other properties, both physical and optical, are good to 135°C. POLY IR® 5 material is a vey frustrating material: one with good high-temperature properties which cannot be used at high temperatures.