Dazzled by visions of a high-tech future, the Montgomery County Council charted a course for development this week that will recast an area of the county known as "Rockburg" into a major center for research and development industry by the end of this century.

In what many called the most significant rezoning of county land in a decade, the council on Tuesday tentatively approved sweeping changes in the Gaithersburg Vicinity Master Plan that will allow the construction of millions of square feet of office space and hundreds of homes in an area bounded by I-270 and Route 28 between the cities of Rockville and Gaithersburg.

"It's an extremely significant package of decisions. It charts the course of the county's economic future for many years," said David Scull, one of the council members who endorsed the plan in a 5-to-2 vote.

The crowning jewel in the development scheme is a proposed $500 million mini-city slated for the current site of the Washingtonian Country Club that will include 2.7 million square feet of office space, an 800-room hotel and 1,500 housing units.

The council, in a surprise vote, also approved the development of a 1.5 million-square-foot "conference center" on a 200-acre tract south of the traffic choked-intersection of Route 28 and Shady Grove Road.

The 2.7-square-mile area, known officially as Shady Grove West, is one of Washington's hottest pockets of suburban growth. County planners have spent two years revising the area's development plan to take advantage of its prime location and its access to major facilities such as I-270 and the Metro subway system.

Along the way, however, they have had to contend with opposition from city officials and area residents on a number of issues. Chief among them was the thorny problem of traffic congestion.

The area's road system has been all but overwhelmed by a decade of rapid development, and both citizens and city officals alike clamored for curbs on growth until conditions could be improved.

To help ease future congestion, the council tightened regulations under the county's Adequate Public Facilities Ordinance, which will allow planners to stage development to coincide more precisely with road improvements.

Under the Shady Grove West plan, development will be staged in three phases over the next several years.

During the first two phases, more than 4 million square feet of office space and 1,800 housing units are slated for construction, according to county planners.

Less development will take place initially, but overall density probably will increase under the revised plan when all three phases are completed, Scull said.

Exactly where and how that future growth will be concentrated is still an open question. The council deferred rezoning several hundred acres of land encompassed by two major farms until road improvements have advanced enough to make the final phase of development feasible.

In adopting the master plan revisions, the council majority tilted future growth decidedly in favor of high technology industry instead of housing, a move sharply criticized by other council members.

"I'm very disturbed about the over commitment to industrial development, which I don't think can be accommodated," said council member Neal Potter, who voted against the revisions.

"We also make no specific comments about how we would preserve green space. It's too likely to get lost if we don't make some provision for it," he added.

The council's endorsement of a conference center south of Route 28 bucked a planning board recommendation against the facility and drew immediate criticism from Planning Board Chairman Norman Christeller.

"I have serious problems with their approval of the conference center," Christeller said. "The plan is not in balance now in terms of traffic."

The land, originally slated for residential development, will include a 20-acre man-made lake and $4 million to $5 million in other public improvements, said lawyer Jack Neumann, who represents the developer, Marty Feldman.

The council began considering a final draft of the master plan last September, and was strongly urged to take action this week by County Executive Charles Gilchrist, who warned that further delay could jeopardize the Washingtonian Country Club project.

A development company owned by Mobil Oil Company dropped plans for a $360 million development there three years ago because of the uncertainty of planned road improvements.

Ackerman & Co., an Atlanta, Ga. developer, purchased 221 acres of the club last year and proposed building a mini-city of office residential and commercial uses that will be known as "Washingtonian Center."

The center will be the first developed under a new mixed use planned development zoning category (MXPD).

In a move that angered some area residents, the council also rezoned a 148 acres of country club ground at the corner of Rte. 355 and Muddy Branch Road, clearing the way for developer Jay Alfandre to build up to 710 residential units.

Under prior zoning Alfandre was limited to 355 units. Two weeks ago the county planning board limited the first round of construction to 49 units because of traffic congestion in the area.

"There was no discussion whatsoever of any of the citizen concerns," said Diane Aronson, who lives in a subdivision adjacent to the property.

"The citizens wanted to put a lower density next to their own subdivision which is zoned at a higher density. It doesn't make any sense," countered planning board chairman Christeller who supported the rezoning.