William Barrett had planned to be frantic this week.

Barrett, staffing specialist for Montgomery County schools, had read all the reports of an imminent nationwide teacher shortage; he knew all the figures on rising student enrollments and shrinking teacher applicant pools, and he anticipated having to fill as many as 500 teacher vacancies for this fall.

"I was frightened I'd end up standing here looking for a chemistry or physics teacher on the first day of school," Barrett said.

Instead, with 308 teachers hired as of last Wednesday and the entire teaching staff of 6,200 scheduled to report for work tomorrow, Barrett said only a few vacancies remain. "I am relatively pleased with where we are," he said.

His thoughts are echoed by school administrators across the Washington metropolitan area, where particularly aggressive recruiting efforts, increases in teacher salaries and smaller turnover than was expected have spared local school systems from the teacher crunch being felt across the nation.

From Loudoun to Prince George's counties, personnel directors say they expect few, if any, vacancies to be left by the time school opens.

"Something paid off. All the positions are filled. All the bodies are on deck," said Loudoun County Deputy Superintendent Robert Jarvis, who hired 79 teachers this year.

"We were blessed with lots of good candidates," said Arlington Assistant Director for Personnel Lilla Wise, who reviewed 1,500 applications for 60 teaching slots. In Fairfax County, 8,000 people applied for the 400 teaching slots that were filled last week.

National education experts say the full roster of teachers here is atypical of conditions nationwide, where cities from Houston to New York are scrambling for teachers just days before school begins. The success of Washington area districts in finding teachers "is really very surprising," said Nancy Kochuk of the National Education Association. "I'm just hearing from so many different places that the shortage is real."

School administrators around the region said the appeal of Washington and its suburbs, combined with stepped-up recruiting efforts and fewer retirements than they had anticipated, helped prevent a last-minute scurry for teachers.

For now, that is. "What the urban centers are experiencing, that's an indication of a problem for us down the way," said R. Warren Eisenhower, Fairfax County's assistant superintendent for personnel. "Three to four years out, unless there's some national effort to offset it, we will be experiencing those shortages, too."

Education researchers have cautioned that high numbers of retiring teachers, a shrinking pool of graduates who want to teach and slightly rising enrollments as the children of "baby boom" generation parents enter school will combine to create a teacher shortage within 10 to 20 years.

Reports of the coming crunch prompted many school districts to search farther from home for qualified applicants. Area school officials report bumping elbows at consortiums with recruiters from Florida, Texas and California.

"I have been at meetings where people who have not had teaching job fairs in the past had them this year and indicated pretty good response; there'a a good influx of people wanting to recruit," said Janet Kerstein, executive director of the Association for School, College and University Staffing, an 800-member group of education placement officers.

When Prince William County schools opened Thursday morning, there were substitute teachers behind three desks -- one in a combined physics/chemistry class and two in vocational education. By the end of the day, all three slots had been filled, said Director of Personnel Ronnie Graham.

Graham said salary increases, particularly one that raised pay for beginning teachers 19 percent, from $14,280 last year to $17,000, may have sharpened Prince William's edge in hiring.

"We had read the newspaper, and we had heard about the tremendous shortage of teachers," he said. "We were lucky this year; the salary package made us more competitive."

Other area school districts, anticipating large numbers of vacancies and worrying about a shrinking field of teaching candidates, recruited at colleges around the East Coast and attended consortiums as far away as San Francisco in pursuit of qualified applicants.

Prince George's County spent $9,000, nearly double the previous year's recruiting budget, to visit "career day" consortiums in Kansas and Wisconsin, as well as Maryland campuses.

Loudoun County administrators visited more than 30 Northeast colleges. And District of Columbia personnel officers recruited actively for the first time, spending about $25,000 to visit campuses and promote D.C. schools to prospective teachers.

"We doubled and tripled our manpower," said Barrett of Montgomery County. For the first time in a decade, he said, the school system offered "open contracts," early promises of employment without specific assignments, in subject areas that were likely to fall short.

Beginning in late March, he said, Montgomery County offered 185 such contracts, including 20 in mathematics, 15 in science, seven in foreign languages and 24 in special education -- subjects in which teachers are especially hard to find, experts say.

"If we had not gone the open contract route, I think it would have really been painful right now," Barrett said. "But everybody's saying that with each year to come, it's getting tighter and tighter. We're going to feel the crunch."

Alexandria schools, which had hired 48 teachers from a field of 1,200 as of yesterday, began to feel the crunch in particularly hard-to-fill areas. Only two applicants expressed interest in a Latin vacancy and just one applied to teach German, said Gila Harris, supervisor of recruitment and selection.

The District offered about 20 "intent to employ" contracts, but only a few of those applicants accepted, said Joan Brown, special assistant to the superintendent for incentive programs. "I think somebody snapped them up before we did," she said.

Unlike the surrounding suburban districts, which drew this year's hires largely from young recruits and applicants already on file, two-thirds of the teachers hired this year in the District had been laid off during reductions-in-force in 1980.

Eventually, say education experts, salary boosts and far-reaching recruiting will not be enough to attract and keep teachers. They point to programs that assign experienced teachers as "mentors" to newer ones, summer internships in private industry and enrichment classes at local colleges as ideas that could make teaching a more appealing field.

"We've begun to plan incentives for teachers to come," such as a mentor program that pays older teachers a $2,000 stipend to supervise newer ones, said Brown of District schools. "That's the direction we have to go in, nationally. We're looking at it as a challenge."