To hear most American designers describe their spring collections, one would think that the height of modernism is the sleeveless dress, the very same style worn by Babe Paley in the early '60s. The look is so ubiquitous this season that many people in the fashion business now refer to it simply as "the Babe dress," as if everyone knows what that means.

The Babe babble serves as a convenient counterpoint to another current theme: synthetic fashion. That designers have chosen to prop up a deceased style symbol, presumably in the absence of a living one, supports the impression that fashion is stuck in reverse. Things that are merely classic -- shift dresses and capri pants, for example -- are now exploited as modern. But modernism in fashion exists somewhere between the present and the uncertain future, between boredom with what we have and hope that we will find something not only different from what we have but better. And for many designers, or at least those not mired in the '60s and '70s, the only way to move forward is by turning to man-made fabrics -- the weird, shiny and pebbled surfaces of the last frontier in fashion.

This year, when the industry presented its collections in March and October, the number of designers showing synthetic clothes was conspicuously greater than perhaps any time since the mid-'70s, when disco dancing set off a synthetic wave of stretch pants, Lurex sweaters and acetate shirts. Some collections for fall -- notably that of Rei Kawakubo for Comme des Garcons -- were made entirely of synthetics. Kawakubo's use of chemical-based fibers made for strange textures indeed: rubbery windbreakers, spongy black scuba dresses and nylon sweaters knitted to resemble waxed fish netting.

Watching Issey Miyake's shows is like sitting through a laboratory experiment -- but one never knows quite what went into the test tube. One of the leading proponents of synthetic materials in high fashion, Miyake used Dacron in the early '70s and introduced Ultrasuede -- before Halston made it popular. "But Halston always gave Issey credit for Ultrasuede," says Miyake's U.S. spokeswoman, Jun Kanai. "For many people the word 'synthetic' has a bad connotation, but our customers have reached the point where they look at the finished product as something interesting. It's the results that matter."

For several seasons designers have been advancing shiny surfaces for day -- an evening look promoted in silk shantung jackets and iridescent taffeta blouses. Now they're touting vinyl. This Windex-clean fabric was used so extensively this season by Thierry Mugler -- in leggings, bodysuits and hot pants -- that one left his Paris show feeling vaguely energized, as though snapped by a giant rubber band. If designers such as Mugler and Jean-Paul Gaultier -- who showed vinyl bike shorts under tutus -- represent cult fashion, their theatrics provide at least a keyhole to what's happening beyond the limited scope of official fashion. In clubs, for example. Small wonder that both designers frequent the club scene in Paris and London, where the going look favors vinyl leggings, chain vests and see-through mesh bodysuits.

Polyester manufacturers are also keeping tabs on the streets. "My big question when I came to work here," says Jim Siewart, fashion manager at Hoechst-Celanese, "was 'Do I have to wear this stuff?' " Well, not exactly, but his wardrobe does include spun rayon shirts by Matsuda and Italian synthetic-suede pants made from a blend of viscose and polyurethane. Siewart routinely prowls the fashion markets and stores in Europe for ideas -- potential trends that may help guide Celanese and its customers. He points to the success of micro-fibers -- the stuff Calvin Klein uses in his silky parkas -- as evidence that attitudes are changing.

Or as he says: "It's polyester, guys, but it doesn't say that."

Even among American designers, who generally have resisted man-made materials, there has been a change of heart this year. One of Marc Jacobs's best-selling items for Perry Ellis is a clear plastic raincoat purfled with grosgrain ribbon; the company sold about 90 coats, at $1,000 apiece, to retailers. Come spring, his $2,000 plastic raincoats studded with rhinestones will be featured in leading fashion magazines. There were also space-age synthetics at Michael Leva, Gordon Henderson and Betsey Johnson, whose white vinyl tunics are not novel for a designer who has been advocating unnatural shine since the '60s.

But plastic is not retro by virtue of being mod. What separates the new synthetics from blatant attempts to parrot the past is an appreciation for performance and function. Fake fur, for example, owes its success not to the animal rights movement but to fashion: Fakes are now accepted in their own right rather than as cheap imitations. Nor would Lycra have materialized in everything from blazers to cat suits had fashion not demanded new shapes for more active lives.

"I don't think silhouettes are of any consequence if they aren't relevant to the way one lives," says Geoffrey Beene, who prefers acrylic jerseys for better drape. "We have to rethink the actual performance of things." It was performance that both Calvin Klein and Ralph Lauren wanted when they bought stretch twill from James Gordon, a major New York distributor of European fabrics, for their jodhpurs. "Synthetics are not only accepted, they're bought with enthusiasm," says Gordon, noting a greater demand in just the past year. One of his most popular fabrics is an acetate that is more versatile than silk -- it holds pleats and novelty dyes better -- and also more costly. An Italian-made acetate sells for as much as $28 a yard, according to Gordon, compared with $16 for Hong Kong silk.

Inevitably, fashion moves on. Form will draw increasingly on function. Vinyl fetishes on runways will find an outlet in cheaper imitations. Teenagers will turn on to rubberized leggings, and the woman who buys Emanuel Ungaro's shiny miniskirts this spring will be drawn, perhaps unconsciously, toward the future.