The Montgomery County school board, in an effort to achieve more effective integration in county schools, yesterday began considering amending the school system's policy for defining "racial imbalance."

The aim of the talks is a stepped-up effort to increase the number of racially integrated classrooms in the county. Current policy, using a floating formula based on county-wide enrollment, calls for school board action such as busing when an individual school's minority population exceeds 64.1 percent.

The amendments would redefine when a minority school enrollment is considered "disproportionate" and what the county must do to remedy that. It is not clear what percentage the board will settle on, or whether busing or improving educational programs will be involved.

The commencement of the discussions reflects a major philosophical departure for the new board majority from their predecessors, who were turned out of office in November. Two years ago, the board, dominated by a conservative majority, was accused of building "educational Berlin walls" around schools with high minority enrollments. At that time it voted to set a higher minimum of minority students for triggering action to alter racial imbalance at individual schools.

Members of the new board majority have said repeatedly that they thought the racial policy changes approved by their predecessors resulted in isolation of minorities. Throughout its seven-month tenure the new board has moved to alter those policies.

Earlier this year, for instance, the board approved the revision of a busing plan for the high-minority Rosemary Hills Elementary area and last month board president Blair Ewing proposed seven steps he said the system could take to narrow the achievement gap between minority and white students.

Yesterday a number of board members reiterated their positions on integration and said they would seriously consider options that would lower the threshhold at which the board must act to improve racial balance in enrollments.

"A panic button should not be hit when we reach a certain number of minorities " said board member Odessa Shannon, but she said the board wants to make sure that "that all cultures have exposures to each other." She also cautioned staff members against assuming that each time minority enrollment is high, educational quality suffers.

Member Marian Greenblatt, who two years ago encouraged her allies on the board to alter the racial balance policy, however, cautioned other members against redefining racial imbalance. "What are you going to do when a very large number of our schools are above that number ?" Greenblatt asked.

Greenblatt was referring to proposals such as one introduced by member James Cronin. Cronin suggested requiring the school system to begin steps to remedy racial imbalance when the number of minority group students in a school is double the average number of minorities in the entire school system.

There are currently 13 schools in the county with more than 50.8 percent minority enrollment, or double the county minority enrollment average of 25.4 percent. County planners have said they expect minorities to make up more than half of the enrollment in the majority of schools in lower Silver Spring during the next five yeras.

When Greenblatt and her allies altered the definition of racial imbalance two years ago, the school board was required to act whenever the minority enrollment of a school exceeded 50 percent.