for loop in while loop

[lravikumarvsp]

import glob
import os
a = ['ACM','ACX','GSK']
i = 0
while i < len(a):
	print a[i]
	b=str(a[i])
	os.chdir('/ai2/data/dev/admin/inf/')
	for file in glob.glob('*b*'):
		print file
	i = i + 1

In the above code for loop is not working.
What is the mistake I did?
Please help