Marymount College, founded in 1950 as a two-year women's college, disclosed yesterday that it will officially go coed in the fall of 1987, open a satellite campus in September and has applied for university status.

"We've been talking about doing this for a long time," said Dean Alice S. Mandanis, confirming the changes aimed at improving the quality of applicants at the four-year Arlington college.

"The emphasis is on quality. It's difficult to attract students of high academic caliber to a single-sex environment," Mandanis said. "Female students know they're going to go out and work in the community and they know it's not going to be an all-female environment."

"I think we're all very excited about it," said Sister M. Majella Berg, now in her 26th year as president of the Catholic-founded college. "We have tried to keep up with society and the times and the needs, and this seems to be the need of today.

"The pool that you have to recruit from is going down," she said. "We looked at that and feel we can increase the pool by having women and men. It makes it easier to keep the standards we want."

Although about 50 of the college's 1,500 undergraduates and 450 of the 800 students in its four graduate schools are men, the decision to go coed officially makes Marymount the second women's college in the area to make the switch recently.

Goucher College in Baltimore voted last month to begin admitting men in the fall of 1987, following a nationwide trend of single-sex schools becoming coeducational. Since the 1960s, the number of two- and four-year women's colleges has dropped from about 300 to about 100.

Goucher's decision was attributed in large part to declining enrollment, but Berg and Mandanis said enrollment at Marymount has remained steady.

Mandanis said she does not expect the college's enrollment to jump significantly as a result of the changes because it can absorb only a few more students. But, she said, "We're attempting to be more selective in admissions. We're hoping that by throwing open the recruiting to men as well as women, it will help us improve the average SAT [scholastic aptitude test] scores."

Students currently average 450 each in the verbal and mathematics portions of the college admission tests in which 800 is the perfect score for each category.

Although Goucher's decision sparked campus protests, Berg said she does not expect a similar uproar at Marymount.

"The parents and alumnae that I've talked to recently all seem very pleased" with the decision, Berg said. The faculty, Mandanis said, also is behind the move. In fact, she said, faculty members proposed the changes to the college's board of trustees, which accepted them April 16.

College officials had not planned to announce the changes until this fall. But, Berg said, everything changed when Marymount was offered an opportunity to purchase a former telephone company building at 3130 Lee Hwy.

The building, constructed about five years ago near the intersection of Lee Highway and Spout Run Parkway, will house the school's academic computer center and classrooms that require computer use, Mandanis said.

The facility, which the college bought for $3 million, also has about 200 parking spaces that will be set aside for faculty parking, Mandanis said. The college plans to operate a commuter bus from the Spout Run Campus to its main 18-acre campus at North Glebe Road and Old Dominion Drive.

Mandanis said the purchase accelerated by a year Marymount's plans to go coed and apply for university status. She said the college's lawyers have filed papers with the State Corporation Commission to amend the college charter to classify it as a university.

"We will be renaming ourself Marymount University, effective immediately," Mandanis said.

Referring to the charter of the college when it was still a two-year institution, Mandanis said, "It says we were founded to promote the education of young women. Well, that's been outdated for many years. We have men and we have many older women who commute."

Mandanis said the college would begin recruiting male students this fall, and will set aside dormitory space for them, probably creating separate floors for male and female students.

The college has grown rapidly since it became a four-year institution in 1973. In the ensuing years, Marymount has added graduate schools in arts and sciences, business administration, education and human services, and nursing. Most of the 450 male graduate students are in the MBA program, Mandanis said.

The college's decision to go coed, she said, should help improve the quality of applicants and help retain students. "Retention is very closely linked to being coed," she said. "We were getting better students, but we were losing them because they didn't want to be in an all-female environment. Today's woman really does want to be in a school which has a male population. That's what did it, ultimately."