The Arlington Board of Education accepted the recommendation of Superintendent Larry Cuban and defied the wishes of the Republican-dominated County Board last night by voting to give the country's 1,700 school employes 10.5 percent raises.

That will give school workers raises 2 percent higher than those the County Board has granted Arlington's 2,400 other public employes and is certain to aggravate the already hostile relations between Cuban and the Republicans.

Although the County Board funds the schools, under Virginia law it is forbidden to dictate to the Board of Education how that money is spent.

In order to grant its workers the 10.5 percent pay increase, the school board will have to trim $1.2 million from other programs it had proposed for the schools.

The only surprise as the five-member school board decided last night how to spend the $39.9 million the County Board authorized was that the pay raise vote was unanimous, Board member O. U. Johansen, the only current member appointed by the Gop---dominated board, joined the others.

"They're willing to sacrifice programs just to stick it to us," said County Board Member Dorothy T. Grotos, a Republican. She and her fellow Republicans recently voted to cut the school budget by $1.2 million in an attempt to keep the raises equal.

"They're just having their last hurrah," said Grotos, referring to Cuban and the democrats on the school board. "Inflation causes misery for everybody and we try to spread the misery around by giving equal raises."

But Cuban and school board chairman Ann C. Broder, who were named to their positions under Democratic regimes, said that contrasting salary levels are not their chief concern. "This county has so much money it could find a 10.5 percent increase for its employes as well as ours," said Broder, referring to the $4.2 million surplus the county has.

"This is just another exercise in futility and another crack by (county board chairman) Walter Frankland at Larry Cuban," Broder said.

The school and county boards have been mired in a bitter, two-year-long quarrel. It escalated when Walter L. Frankland Jr. was sworn in as County Board chairman last January. Frankland then said the schools were deteriorating and called for the early resignation of school board members Richard Barton and Mary Margaret Whipple.

Their terms expire next month, and when the two new school board members assume office July 1, the school board will be dominated by Republican-backed appointees for the first time in a dozen years.

Agreeing to Cuban's recommendation, the board cut $106,200 from administration, $453,000 from instruction, $145,000 from maintenance, $300,500 from compensation and $88,673 from community activities.

Cuban told the school board yesterday that no employe should lose his job as a consequence of the reductions. Most of the cuts from the instructional area proposed by Cuban were made by eliminating proposed new or expanded programs.