Table 1.

Retardation, R, diameter, d, and birefringence, Δn, of various fibers analyzed using a polarizing microscope.

Sample	R (nm)	d (μm)	Δn × 1000
Raw material fiber	139.5	152.2	0.9
	133.4	59.7	2.2
As-spun web	438.5	3.6	121
	64.2	4.0	16.3
	310.1	2.9	106
	24.1	2.3	10.5
Annealed web (116 °C)	336.0	2.2	150
	30.3	5.2	5.8
	758.0	3.7	203
	555.0	3.7	149
	804.0	5.2	154
	267.0	2.2	119