Eighty years ago bra-burning was unheard of as a form of protest but women steamed over social injustices none the less. When three literary women were excluded from the District's "for men only" press club they decided to form an exclusive society of their own. Out of their determination grew the National League of American Pen Women.

Today the organization that was begun by Marion Longfellow O'Donoghue, niece of Henry Wadsworth Longfellow; Ann Sanborne Hamilton, a Washington Post editor, and Capitol news correspondent Margaret Sullivan Burke, boasts 233 branches and 6,500 members. Members are recognized professionals in three major categories: literature, art and music composition.

This month 36 members of the league's 20-year-old Chevy Chase Branch will exhibit 44 works in a kaleidoscopic collection of art at the league's national headquarters, 1300 17th St. NW. The exhibit, open Wednesdays and Thursdays from 11 a.m. until 5 p.m., will continue throug Oct. 26.

Kathleen Oettinger, vice president of the Chevy Chase branch, said she's been "painting since kindergarten. But one of the real benefits I see in the show is being with other people with such great talents," she said.

"The purpose of the show is to encourage people to do their best," said Dr. Margaret Hasebroock, national president of the league. "The idea Pen Women is to inspire and enhance, to display objectives to others outside and in the branch. It's only that we do better today than we did yesterday that we can survive," she said.

Hasebroock, the wife of William E. Hasebroock, a Nebraska state senator for 17 years, came to the league after an illustrious career as a coloratura soprano in the United States and abroad. She was elected to the two-year office in 1976.

"(As league president) I wanted Pen Women to take more interest in community and cultural activities," she said. ". . . to upbuild the community's cultural reaction."

This year, she said, three District high school students will receive league scholarships for their contributions to the arts. Two national scholarships are also given each year through competitions held by Scholastic Magazine. In addition, she said, local league branches throughout the country hold competitions and programs at various grade levels.

Hesebroock also recently began a scholarship program for women 35 years or older who want to resume studying in a fine arts category. The innovativeness and determination of the league is only limited by the imagination of individual branches, she said.

Most Pen Women apparently have never lacked much in the area of innovation. The group's 92-year-old mansion, fully purchased 30 years ago, was obtained through the determination of league member Dorothy Betts Marvin. Marvin, a writer of historical articles and wife of the former George Washington University president raised $64,000 in two, non-successive terms as league president because she wanted the group to be debt free.

The headquarters, built by a military officer, served as the residence of Robert Todd Lincoln. Araham Lincoln sat for Vinnie Ream, a league artist, for the last time on the day before his assassination. Later the artist was commissioned to sculpt the statue of Lincoln that now stands in the Capitol Rotunda.

Other pioneering Pen Women have included the wives of Presidents Harding, Wilson and Franklin Roosevelt. Outstanding literary Pen Women include Faith Baldwin, Taylor Caldwell, Jeanne Dixon, Dale Evans Rogers, and Eurodora Welty, among others.

Artists whose works appear in the Chevy Chase show include Edith Adams, Miriam Roberts, Ann Blackwell, Pattee Glennie, Edna Searles, Roberta MacDonald, Eunice Harris, Kathleen Oettinger, Marianne Giguere, Elizabeth Allen, Margaret Osburn and Vinna Grace. Roberta MacDonald is president of the branch.