The teenages at my daughter's middle sch are wearing
necklaces----mostly neon colors----made from the strechy materail used
to make woven potholders. What is the meaning behind these necklaces?

It looks as if adults are doing this, too:

"On the look of the month front, I must report the worst.  Our CDO is
still wearing potholder loops around her neck!  Yesterday she wore
three of them along with a short bead necklace.  And, she says a lot
of the kids in her school are wearing potholder loops too!  While it's
nice to know the kid is a trendsetter, is this really something a
beader's daughter should encourage?  Sure, why not?"

http://greenlightwrite.com/beadingdiary0103.htm

Apparently the neon-colored potholder thingies are called "Hot Loops."

http://www.camppacs.com/cgi-bin/shopper.cgi?preadd=action&key=ConfettiBJhotloops

You could try asking your daughter